How sad that he would scare you like that!
Why is he "worried" about your veins? My IV was put in by an RN and then all the Anesthesiologist had to do is tell me, "I'm going to give you something to relax now", pushed a needle through my IV and I was out in seconds.
Like others mentioned, you have waited a long time for this and you're so invested now! The positives far outweigh the negatives. The best thing you can do is to mentally prepare yourself 100% because your body will respond so much better -- less internal bleeding and better healing, etc., and walking is king for gas problems (according to some friends of mine on here). I did not experience gas problems at all, probably because I took 2 Gas-X pills the night before surgery. I also walked as soon as I could and as much as I could, even when I felt like someone needs to tape me to my IV pole so I don't collapse.
I wish you peace with your decision and all the best with whatever you choose.