Wow that's an early surgery!
Don't worry about being scared..you are not alone with that one. I was absolutley terrified before my surgery too. I just had my lower jaw advanced a month ago now. I went to the hospital all alone and neve had any surgeries before either except for wisdom teeth extraction. I cried in the waiting room for about 2 hours by myself before they brought me into the operating room. I didn't even want to be wheeled in..I wanted to walk cuz I felt more in control. For the needle I got them to use freezing cream on my hand cuz I was scared of that too...and it really helped. Also before hand they gave me this small pill to put under my tongue to calm me down..Adavan or something like that. And yes, there is always the risk of complications but I think it's so rare..this seems to be a very common surgery nowadays and the doctors do it all the time. As for the pain, almost everyone's story on here I've read has experienced minimal pain. Myself as well...it's more like tight muscle throbbing more than actual pain. It's an annoyance but it is livable. You will be fine

I was in the hospital for 1 night. My surgery was about 2 hours. The painkiller as morphene threw my IV. And I had tight elastics holding my jaw together for a week...I could open my mouth, but barely..enough to get the tip of spoon in anyway to eat.
Good luck

I'm sure you will do just fine