Gastroentereologist - Child Colonoscopy?

I am 13, and having a colonoscopy and an endoscopy in the same day. I am letterily shitting my pants about it and I am mostly worried about the anesthesia side of things. Will they completely knock me out, or just twilight sleep? I am really scared as I gag easily. Also I have had Guillain Barre recently which is a nerve disorder, will that affect the anesthic? Can they tell through a colonoscopy wether I have a nerve bowel related problem? Please help anyone even if your a anesthesist or gastroenterologist. Even with just experience :)