I had my wisdom teeth pulled when I was 17. They say it gets tougher as you get older, but I don't think 3 years would make a difference. I did not get knocked out, and it really wasn't all that bad. I felt a ton of pressure, and maybe a tiny bit of pain, but the worst thing was anticipating the pain... that never really came. They should let you take an iPod, or some other music player in with you, so you might wanna ask about that. I was listening to After Midnight, as performed by Eric Clapton when it ended.
For me the worst part was recovery. THAT was miserable. With the pain meds, it wasn't all that painful, though. You've got to keep a ton of gauze in your mouth that prevents you from chewing, and makes swallowing a quite troubling task. When you do swallow you taste tons of blood. You've gotta keep pressure on the gauze by biting down on it pretty hard, thus causing pain (unless you're on pain killers, which you SHOULD BE).
And then you've got the stitches. These things are just supposed to fall off in your mouth. I think I ended up swallowing all of mine. That was fun.
I heard so many horror stories about getting my wisdom teeth pulled, but like getting a root canal, I think those stories are few & far between. I think it CAN be a terrible experience, but more likely it won't be all that bad.