I may 'double-up', which means take two classes of the same subject. Meaning Junior year I could take Alg. II and Trig, and then take Pre-Calc as a Senior.
Just another option to think about, if you can afford it, you could take a class during summer. If you do some research, I remember reading about a couple military schools offering summer programs with credit for high school courses. I'm sure it'd look great on that application and it would give you a good idea of the type of schedule you would have at an academy.