You would not be human if you did not notice any nerves or worries before this huge surgery. I am the same when I have my twice yearly appointments at the dentist. Fear of the unknown.
Read the ' before and after photo's ' in this forum, this should give you some inspiration, it did me. I wanted to be 100lbs lighter and tada, waves magic wand, now I am. I have not had the easiest ride but I wouldn't change a thing. My entire life has changed for the better.
If you have to back out, its ok. People on this forum have done this and some have eventually had the surgery and wished they did it the first time. It has to be the right time for you, Good luck