Plenty of good advice in this thread about how to get started on game programming.
However, I didn't see mentioned. If you are serious about being a game programmer as anything more than a hobbyist, you should strongly consider a Computer Science degree from the best 4 year college you can get into.
1) You'll learn a lot of stuff about how computers work, theoretical and practical, that you probably don't even realize you don't know. You can learn this stuff elsewhere, of course, but...
2) Most game programming jobs list a BS in Computer Science as a requirement, or at least a strong recommendation. Years of experience or good contacts can get you around this requirement, but do you want to count on that?
3) Game programming has a lot more in common with programming (any kind), than with playing games. So, you should be training yourself to be a programmer, more than a games expert.
4) That Computer Science degree will also come in handy if, at some point in the far future, the negatives of game programming outweigh the positives for you. Stability, higher pay, and shorter hours probably don't seem that important to you right now, but someday they might.
So, in 10th grade, you should be devoting your school time energy to math, science (especially Physics), and computer programming as much as you can. As a bonus, that stuff will be directly applicable to your game programming right now.
Good luck,
Geoff