[kgoerz]

Before I came in the Army I fired an original Confederate Rifle from the Civil War a couple of times. Other then that and pellet Guns. The M16 in basic was the first modern Rifle I ever fired. Shooting is easy, what you shoot at can become difficult.
Don't worry about it. Join a Gym and concentrate on getting in the best possible physical condition. Good physical condition will go a lot further in helping you shoot. A lot further then shooting an AR a few times. Never heard of someone getting kicked out for shooting bad. It will be years before you are in a position where poor shooting will get you kicked out of a school. It will be the first week where bad physical shape could get you kicked out.