Hi 511,
Welcome to T2W.
Your goal is achievable utilising high risk strategies trading a demo account. However, in the event that you achieve it, don't kid yourself that you can replicate your success trading real money. It ain't gonna happen and, if you try, you'll almost certainly blow up and lose all your money. Treat it as a game and have fun with it, but realise that's all it is. If you want to take trading seriously, my advice would be to paper trade a second account in the same way that you would do if it was a live account funded with real money. That way, when you turn 18, you'll be able to hit the ground running.
Enjoy!
Tim.