Hey, glad to hear about what's on your mind!
1. My main thought is that the most important thing given your situation is to focus on your own wellbeing and independence. The advice for students to donate is meant for people who have more freedom and would otherwise spend their money on unimportant things. Your situation sounds very different from that. Like Imma, I suggest using the money to invest in yourself - whether that's food or other basics, saving for emergencies, or whatever will best support your needs. Getting to a better place in the next few years will enable you to do more to help others later if that's what you choose.
5. At your age I also worried a lot about how to responsibly spend the rest of my life, but I suggest holding such plans very lightly. There's a lot of time for all kinds of things to change. But if there's comfort in imagining a retirement where you get to enjoy some tranquility, fine to keep it in mind as a "someday / maybe" possibility.

(Note that I'm trying my best to give advice given rather limited information)

Hello and welcome to the Forum! I first want to say that I relate to a lot of what you said (e.g. discovering Singer at a young age, controlling household). 

I want to second a lot of what Julia_Wise says. Focus on your wellbeing and independence if you can. In particular, if you are interested in and good at academics, seriously consider studying really hard in the hopes that you can get a university scholarship to somewhere that's more free, so you can be more independent in the future.

Also, I want to say something like "it probably gets better?" The world is full of beauty and horrors, and it's too easy to focus on just the horrors and not the beauty. But there is so much beauty and life in it too, and so much happiness. And perhaps the world is full of suffering now, but as we get stronger and wiser, we will increasingly have the power to make the world go well.

The world is confusing, scary, and out of control at 16. As you get older, you'll probably still be confused and scared, but you'll be less confused and scared. And probably things will feel better and less out of control as you have more personal independence.

Focus on your wellbeing and independence. Focus on becoming stronger and freer. And keep in mind that after you become stronger and wiser and hopefully happier, you'll be in a much better position to address the problems of the world.

Hello and welcome! It's great to have you as part of the community. I agree with the other commenters that investing in your own wellbeing and future at this early stage is a good idea. For example, I'd encourage you to look after your physical and mental health; do your best in your education; and explore different career options, perhaps by listening to stories of people's careers in the 80,000 Hours podcast. You can also encourage others in doing good by commenting on EA Forum posts and talking to your friends about your plans.

I think in high school I was really hard on myself, and if I could give my past self advice I might say that it's also good to be caring and kind to myself - so that's advice I'll pass on to you too!

Reaction on your intro:

1. Peter Singer's work also deeply affected me at the time (2012). There is a lot of suffering in the world, and many people are able to effectively  help alleviate it - and that's a good reason to go do it. However, there are other ways to help than just giving money.
That being said, I think Singer's take on EA is a bit naive and outdated. Others have built upon his thoughts, and made them more nuanced.
2. This sounds really hard. Having grown up in a free and non-traditional culture, I can't help you here, sorry. - I hope someone else at this forum can help you out here?
Would you be comfortable just keeping your lunch money for yourself and buy the most healthy food that is available to you? - when you are healthier, you are in a much better position to help others later in your career. 

3. Cool! Don't feel obliged give up writing and music entirely.

4. I am not an expert on ethics. If you search for "suffering focused ethics" you might find some interesting things and ways to help building a future with less suffering- but many other ethical systems are concerned about suffering and want to alleviate it. 

On your questions:

1. I would suggest to prioritize investing in yourself and your career over donating. I assume you are still in high school so you still have many many options open. If you are thoughtful about what degree you choose, this can make a much, much bigger difference than what you do with that small bit of money. Again, there are many more ways to have an impact than donating.
2. I don't know much about investing in the market. Investments with higher expected returns are also more risky. Less risky investmens typically have less returns. Purely altruistic investors can take more risk and have - in expectation - higher returns and can help more people. 
3. I don't know.
4. I don't know. In this situation I would just take the option that is cheapest / least effort for me, so that I can focus my attention on other things as soon as possible. Yes, I am being selfish here. That's because I want to be more altruistic elsewhere.
5. That's quite a long time in future! I wouldn't overthink this. Who knows what the world will look like by then?
6. Invest in your career. Consider different career paths, not only the most obvious ones or the ones that your parents/teachers/whoever push you into. I really hope you have the freedom and opportunities to do so. (Not exploring enough has been my biggest mistake in my late teens and early twenties, I ended up doing a degree that I wasn't a good fit for). Even when your parents/teachers/whoever are friendly and want you to be happy in your future, they are probably wrong about the world and about what you can do. 

Glad to have you here :D

I'm just going to plug some recommendations for suffering-focused stuff: You can connect with other negative utilitarians and suffering-focused people in this Facebook group, check out this career advice, and explore issues in ethics and cause prioritization here.

Julia Wise (who commented earlier) runs the EA Peer Support Facebook group, which could be good to join, and there are many other EA and negative utilitarian/suffering-focused community groups. Feel free to PM me!

Hi there! I appreciate you having the courage and forthrightness to write up what you think and ask questions. I don't have answers to most of your questions, but in addition to agreeing with everyone else on taking care of yourself (while also acknowledging the power of donating even when you don't have much as a signal to yourself that you're living a life in line with your values), I encourage you to 

- read widely: sounds like you're interested in crypto currency and making money - there's a lot to read about that online and in youtube videos and probably books. I wouldn't necessarily advise making any particular investments, but it's absolutely something you can find out more about
- find some connections / community: it can be hard to try figuring out all of this on your own. There are others your age interested in effective altruism, and of course you've found the forum. Maybe there are groups in your area?

I'll DM you to discuss more.

Hi! I relate so much to you. I'm seven years older than you and I'm pretty happy with how my life is going, so although I'm no wise old sage, I think I can share some good advice.

I've also been involved in EA, Buddhism, veganism, minimalism, sustainable fashion, etc. from a young age, plus I was part of an Orthodox Christian community as a teenager (as I assume you are in Greece). 

So, here's my main advice. 

The philosophies of EA, Buddhism, etc. are really really morally demanding. Working from the basic principles of these philosophies, it is difficult to find reasons to prioritize your own wellbeing; there are only pragmatic reasons such as "devote time and money to your own health so that you can work more effectively to help others". Therefore, if you predominantly engage in these communities through the philosophy, you will be exhausted. 

So, instead of going down internet rabbit holes and reading serious books, engage with the people in these communities. Actual EAs goof around at parties and write stories. Actual Buddhists have silly arguments at nice restaurants and go on long treks through the mountains. While good philosophies are optimized to be hard to argue with, good communities are optimized to be healthy and sustainable.

I'm guessing you don't have strong EA and Buddhist communities near you, though. Same here. In that case, primarily engage in other communities instead. When I was your age (ha that sounds ridiculous), I was deeply involved in choir. Would highly recommend! Having fun is so important to balance out the philosophies that can consume your life if you let them. 

In non-EA non-Buddhist communities, it might feel like you're the only one who takes morality seriously, and that can be lonely. Personally, I gravitate toward devout religious friends, because they're also trying to confront selfishness. Just make sure that you don't go into depressing rabbit holes together.

Of course, there are nice virtual EA and Buddhist communities too. They can't fully replace in-person communities, though. Also, people in virtual communities are more likely to only show their morally intense side. 

I hope this helps! You're very welcome to DM me about anything. I'll DM you first to get the conversation going.

P. S. You've got soooo much time to think about monasticism, so there's no reason to be concerned about the ethics of it for now, especially since the world could change so much by the time we retire! Still, just for the philosophical interest of it, I'm happy to chat about Buddhist monasticism if you like. Having lived at a monastery for several months and written my undergrad thesis on a monastic text, I've got some thoughts :)