Tell Me About Military School?

Well right after I graduate I plan on joining the Marine Corps or Navy. I want to attend a military school as a sophmore because this year (freshman year) I will be a cheerleader. I want to know what military school is really like. Also I need to convince my parents to allow me to do this. If you could please help it would be greatly appreciated. Oh and if any of you know of legitamite Texas military schools that would be great! Thanks!