It is like a really hard boy scout camp.
You'll do fine.
I went in at 27 and I was only in mediocre shape. I can't say I came out significantly better, not like the Marines or Army.
USAF/ANG
Honorable 1983
you will have a few more perks, not much. You will have to remain at the rank for the required time till you can advance. There really is not much use in that.
Why are you going in as enlisted? With four years of college you could go in as an officer.