Hi there!
I was scared before my colonoscopy as well but I agree with Aces. The procedure itself was a piece of cake. The drugs they put into my IV were very fast acting and my apprehension just melted away as I fell asleep. It was some good stuff! I didn't remember much if anything and I felt totally fine afterwards. My room wasn't scary at all. It was dim so they can see the screen when they do the scope but I had a blanket and was nice and warm.
As far as putting you to sleep first... I don't know for sure but I would doubt it. I THINK they have to hook you up to some monitors and things so the nurse can monitor your vitals while you're on the drugs that keep you out of it. They are short acting drugs as well. This isn't like general anesthesia.
The only thing I dread about the next one I will have is the prep part. That was yucky and it was miserable starving myself for 24 hours. If you can get through that, the procedure is super easy! Good luck to you! Big hugs!