Wisdom tooth and general anaesthetic?

I'm due to have my wisdom teeth and a small polyp removed tomorrow morning under a general anaesthetic, and i'm incredibly nervous. I've never had a general before, just locals. What can I expect, as my dentists haven't really explained anything to me, just that i'm not supposed to eat after midnight. Has anyone else had their teeth out under a general? I need a rough idea of whats going to happen, and what risks there might be. I'm a fairly healthy 19 yr old girl. Sensible answers please, I don't need to be any more scared!