BK ... please listen, I may not expect you to understand this, because I never would've at your age, but this IS that thing people wished they'd done more of in their youth: learn. Now, I'm not saying that having fun isn't important, but the experience you acquire now matters. Your education isn't a waste, it is what will define your future, and what has defined the future of everyone I've met in my lifetime.
O_o ... What? No. Seriously. What? You're asking why history is important and you actually want to be an artist? Are you kidding? History is the story of EVERYTHING, history is the record of humanity. Our fears, our dreams, our sorrows, our worst crimes and our biggest triumphs.
I loved history BECAUSE I wanted to be a writer! I wanted to learn as much as I could about the world and how it came to be and why it works the way it works now, because the better you truly understand something, the better you can recreate and imagine it. Do you have any idea how many, many best-selling book series are based on our history and how many pieces of incredible art are based on our past? ALL OF THEM! xD
... Everything you see today has its place in history. If you want to make an entirely new world, fine. But if you want anyone to take you seriously at all as a world builder, as a writer, and as an artist, you need to know your own world first. I write as a hobby and I still do research on a daily basis for everything I write because I need to know what I'm talking about, but my knowledge of history has been just as important to me as my knowledge of English lit.
(It's called "dyscalculia," not dyslexia.) You want challenging math home-work? THEN GET BETTER GRADES. My little sister is your age, she had the same problem. When she started making straight As, they started putting her in advanced classes. This ... is basically the entire concept I'm trying to explain here: Prove you can excel at this and you'll get a shot at what you -want- to do.
As per your plans: First, musicians and writers are both considered artists. Second, why on earth do you think we have schools for music, art, and literature? >_>' If you want to be taken seriously as an artist (as in, if you want a real shot at making money on it,) then college is your best bet.
You know "Lady Gaga"? I don't care if you love her or hate her, but she is one of the most iconic musicians of our time at the moment. She also went to school for music. Wearing a stupid looking outfit and prancing around on stage only got her so far, she needed actual, polished talent to do what she does. Talent is innate. Polishing, on the other hand, comes from training and education. You're a smart kid, Taco. You are also a talented kid, but if you do not find people who can teach you to hone your talent, it'll mean nothing.
Besides ... you may not be able to make it as any one of those things by itself. Playing an instrument / singing, writing, and creating art are considered hobbies for many people for a reason. They do not pay well. I can show you websites if you want, but... lemme break it down for you:
Nearly every single aspiring writer in existence makes exactly 0 dollars per year. The average self-published author makes anywhere from 1 dollar to 999 dollars per year. 46.1% (less than half, mind you,) of published writers make anywhere from 1 dollar to 5,000 a year and the rest make about 1-999 bucks like the second group.
If that sounds like a lot to you, you need an economics course, because by the calculations I have, the average person on a budget who is fairly lucky needs roughly $20,000 a year minimum. Um. Yeah. No. You're about 15k short of making it there, sport, and that's if your odds are good.
You know Stephanie Meyer? Twilight may be trash, but she is now one of the most well recognized authors of our time? You wanna know how she did it? ... I can tell you, and it has nothing to do with sparkly blood-suckers, though I admit that she managed to put out the vampire love scene hook at an exceptionally convenient time. No, actually, it's because she's a house wife. She's not relying on her writing as her job because she already has someone paying the bills and buying food for her. It's not a career, it's a fun little "break" from cooking and cleaning that she just so happened to get absurdly lucky on.
If you want to be Stephanie Meyer, great. Go find a guy (or girl, I ain't judgin') with a stable and well paying job who is willing to support you when you get older, then write until you are able to make a hit series. But if you want to be independent / choose to marry purely for love, not money, and not have to work another job just to feed yourself, the "arts" are one of the hardest ways to actually make a buck and if you want to be taken seriously, you really have to work hard.
(Ranting? Like what I just did now, but shorter? I wouldn't worry about that. :P )