C-section vs natural birth

So ever since high school and taking all of the classes (child development, adult roles) I have decided I wanted a c-section over natural. Just have never liked the concept. And so when I got with my fiancé I was flat out with him and told him I would rather have a c-section than natural and he was with me for that. So I got pregnant and now I'm 15 weeks and so I got something in the mail recently saying I was having natural birth and like how much it cost but how would I be able to change that? Do all doctors do c-section? And can you actually choose you want c-section over natural?