Presumably you'll end up in juvenile court, where the court will consider your home, school, community and prior police record and try to figure out a suitable disposition. The court is going to be concerned not only by your theft offense, but by the extent of your illegal drug use. You can expect a disposition that is designed to try to keep you from again breaking the law; a big part of that is going to be whether you impress the judge as a kid who made a mistake on his way to college, a kid who's on track to be a burnout and a drop-out, or if you fall somewhere in-between.

