excellent in a college students mind is probably somewhere between -1 and 0%
But in all seriousness why is your goal something like bodyfat percentage? Are you obese? Is your current body fat percentage causing you medical problems?
Having a bodyfat percentage that is too low can hinder you in endurance exercises and events, yes you weigh less and have more lean mass but you have nothing for the lean mass to gobble up when you may accidentally miss a meal. Or when you are 3/4 into your marathon and don't have any more munchie bars. After the fat goes the next thing on target is muscle fibers.