Finish school, Year 10 at the very least so you can follow up a traineeship etc. Alot of people who want to become pro slacken off when they see the amount of work required, if you have the drive you'll go places, if not you'll more-than-likely end up flopping and having nowhere to go without an education.
Reitterating (spelling?) what Boody said, education should come first even if you're in an intense/pro league for football already. I'm facing the end of my career at the age of 16 because my knees are turning to mush and my body's struggling to cope with the amount of strain that it requires to become a professional footballer (training day in, day out more often than not fur mir), I'm glad I'm finishing Year 12 and completing my HSC (Higher School Certificate, final exams b4 you finish school etc) so I have something to fall back on in case my body karks it before I hit it big-time.
What's the use of school is a silly question if you're not completely ignorant mate. It forms the basis of all your educational knowledge. Kids striving for the big time who're already in the youth academies etc are still required to attend classes 2 hours a day or so I believe, so school is still considered important to pros as well.
Schooling is alot more than academics, it provides the basis for all means of social and sporting communication and participation. Don't brush it off, if your body karks it or you simply don't make it big-time you're going to want to have something to fall back on.
Heed my advice, I still have dreams to go pro but my body is falling apart so I'm finishing my education so I can push myself into the media industry when I grow older if football doesn't all go well for myself. It's good to see that you have the passion, keep pushing yourself and train as much as possible. You must make the dream a reality, it won't do it for you. Try out for a high-grade or high-level team and see how you go from there mate.
EDIT: Would it be appropriate to say that you should be considered by yourself and others as a "student-athlete" and not an "athlete-student"?