Don't be nervous about it. I actually had a great experience in the OR. They wheel you in with your bed and then you climb to the operating table. There will be multiple nurses and surgeons around, also another doctor who is responsible for anesthesia. As this is a pre-planned surgery people will be relaxed and probably will be laughing/joking with you, as this is not a life-or-death emergency kind of situation you see on tv. Your maxfac surgeon will most likely tell you that everything will be okay and they are ready and dont worry. After that the anesthesiologist will start putting you to sleep. Thats a very fast thing, I was "out" in like a minute or two after they started it.
You wont remember anything, you'll wake up in your bed feeling no pain even several hours after the surgery.
Before the whole procedure the anesthesiologist will also interview you about any known health problems. If you're young (like less than 60) and have no major health problems you shouldnt be afraid of all this, they are experts trained for several years to do what they do.