I haven't had to have a colonoscopy yet but I'm due for one soon because my aunt has FAP (it's where you get polyps on your intestines and they need to be removed)...so I have to have one before I turn 25 (so in the next year).
My GI says that because I've had the symptoms of IBS for over 10 years that I don't need one just yet because if it were anything more serious then I'd be very very sick by now...and the meds seem to be working for me and I'm not getting any worse....
BUT my aunt has had a couple of them and she says they're really not bad at all. YES they put you out for it!!! She said the prep is the worst cuz you're stuck on the toilet for a while but she said that they put you out and you wake up and you wouldn't even know you've had one. I'm sure you'll do just fine....I'll keep you in my prayers....