What are the EMT Basic rotations like?

I live in Alabama, I'm 17 years old and I'm thinking of taking EMT Basic next semester. I heard you have to apply for it, so how difficult is it to be accepted? Also, I never had a physical, so how can I be prepared? and I know the class gives you a certain amount of hours during rotations, but is there a way where you can volunteer for more hours? Alot of questions I know, but I appreciate any answers I can get.