Blake,
In general, the mission of the Prep School at USAFA is to foster diversity applicants, prior enlisteds, applicants that might require some seasoning (i.e. high GPA, low test scores. IC's, etc) The admissions office makes the offer (based upon their selection matrix), there are also things like the Falcon Scholarship where a candidate is sponsored to attend one of a select group of Prep Schools. If none of these are offered to you, there is also the choice of attending one of the private prep schools on your own (free agent). The fact is sponsored or not sponsored, you have to perform in prep school in order to earn an appointment at USAFA or any Service Academy.
That said, you really need to think about what your goal is (USAFA, AF, paid education, etc) and consider if USAFA is a good fit. If the AF is your goal there are many ways to get there (AFROTC, OTS). At USAFA for the first 2 years, you are basically an engineering student, with less time to study than any peer at a civilian college. To make this even more daunting, for reasons known only to the most obtuse, at USAFA they take away one of your most valuable tools that you learned to use in high school and are allowed to do your standardized testing with (SAT, ACT), the graphing/scientific calculator and replace it with a $3 "honorator". Then just to make your life more miserable, they force you to do some of your most important calc assignments on a fiendishly frustrating online system that would make the Obamacare website seem like Amazon.com. Then if you survive Calc I, the first thing they do in Calc II is slam you early on with the Functional Skills Exam which can substantially reduce your grade if you do not pass it. Point is that Math is not easy at USAFA, it might actually be needlessly difficult. If you struggle at math, USAFA seems to find ways to make it even more of a struggle.
Thus the fit and goal comment, cadets who are "C" students at USAFA might well be Dean's list students at any other college without an "A" at the end of their name (USAFA, USCGA, USNA, USMA, USMMA). Perhaps more so at USAFA than others for reasons already stated. So consider your choice carefully, and remember that you still fly, be in the AF, get commissioned, no matter if you are an ROTC officer, or a OTS grad, it is a different path, but you can end up in the same place. The point is to find a path that will allow you to thrive.
Good luck,