Hey Montana,
Don't worry about a thing, its a painless procedure. I've had this done a few times, and like yourself was worried when I first had it done.
You'll been taken into a room and have a bright light shone in to your eye. They will hold a magnifying glass on your eye, which is a little uncomfortable and that's about it. The procedure should last no more then ten minutes, in fact one of mine took literally about two minutes.
Hope I've helped set you mind at ease.