I, too, was terrified the first time I went under for my wisdom teeth. But, really, it'll be ok. I've had two more minor surgeries since then, and though I was still a little nervous beforehand, I didn't have any problems. So try not to be concerned.
Also, it is better than the alternative. I have a close friend whose hymen was very tough, but she didn't know until she had sex for the first time (didn't go to the gyno first, as she should have). As a result, her first sexual experience was absolutely torturous and she was sick for two days!
So don't worry about your surgery. It will keep you from much pain later!
If the stars are aligned against you, realign the stars.