Your high school grades mean nothing if you are applying for a commission and a slot for flight school. Aside from the US Army's Warrant Officer Flight Training program, all of the other branches pilot's must be a RLO, which requires a four year college degree. It isn't too late, don't worry. Just maintain at least a 3.0 GPA in college, do a lot of out of class room volunteer work, and try and get some leadership experience. Maybe even entertain the idea of your getting your ppl, and i'd say you have as good of a shot as anyone else.
Right now you are at a perfect position to turn your high school grades around. That should be your primary focus. Kick butt the next two years, get into a good school, have fun, stay out of trouble, and put in for a commission and a pilot slot. Whats the worst they can say? No?
PS - For most of the branches you have roughly until age 29 to enter flight school, so even if you dont get picked up right out of college, know you still have nearly a decade to become competitive.
