Hey kid, I'm a freshman in high school working towards the same goal. Remember not to get too far ahead of yourself. If you want to make your dream come true, don't daydream about it. Besides getting good grades and doing sports, make sure you get in lots of community service too. Make sure you do well in math, science, and English. There might be a JROTC unit near you if you want to get a look into So don't get too far ahead, because you're still young. But then again, don't lose sight of your goals.
P.S: Besides ROTC you might try the Academies. Check out www.academyadmissions.com for the USAF. There's plenty of info there. Remeber the USN and the USMC also have pilots.