My best advice is to raise your stats as much as you can.  Admissions will take large improvements into consideration.  You should try to make it to at least trig/pre-calc in math.  Calc 1 is recommended, but not absolutely required.  If you do not make it into an academy, there are other options such as ROTC.  You can join ROTC in college (and get scholarships). 

Medical requirements for pilot qualification vary a little between the services.