Be very, VERY prepared to be tired. Getting up at 5 doesn't seem that bad, especially since some of y'all do it for school.
The physical aspect isn't necessarily hard, but it is tiring. Your worse challenge will be staying awake. Get used to sitting down and listening to people talk. And talk. And talk...They'll have SGT's patrolling around keeping cadets awake. You do not want to be caught asleep. (Unfortunately, I fell asleep when the Dean came out. However, I can play a mean "i'm-awake-just-leaning-my-head-over" position.)
However, it is fun. Pick the classes you will want to take up there. You get to do stuff few others can.
Know your squad mates. Unfortunately, I couldn't maintain contact (got rid of FB because of school), but the time with them is amazing. My patrol leader's were great, and I still remember it like it was yesterday.
Have fun! Relax a bit and just take in the entire experience. The first few days will suck, I feel like. I was at the point where I was questioning my sanity. Again.
You will be very, very tired. However, you come to learn to love it.
Don't expect it to be top-notch. The first day they scare you, but you cruise it afterwards. Your entire day is planned out for you, so don't bother texting until you get to bed.
Train, train, train for that CFA. This is the best time for it; no paper work for you!
Hope this helps