Solarwave-
A little bit of fear/apprehension is good for you. It will keep you on your toes. Never get complacent, and use that little bit of anxiety to gain the edge over your classmates who choose to waste their mando study time participating in random BS sessions.
I failed the first math test in A school. Since you don't know yet, that means the easiest one. My advisor told me that I should think about other rates, as I would likely fail the second test, henceforth failing A school math and failing A school. However, I pulled the whole deal off, doing at least average or better from then on.
You CAN do it. You have to set a goal, focus on that goal, eliminate as much interference as you can, and accomplish the task you undertake. The only question is whether or not you really want it, or can wade through the minefield of distractions that await you in Charleston (girls, booze, the beach, etc.)
Oh, and 80% is an outrageous attrition rate. I would put it TODAY somewhere around 20-30%, and most of those are integrity violations (ie disciplinary problems).