Post and core after root c?

Hi everyone. When I was about 9 , I fell on a tile floor and a little more than 1/2 of my front left tooth came off. I had to have a root c and they made my smile look normal. Well I'm 15 now, and it's discolored and shorter then my other front tooth. My dentist said that they had to do something called a post and core crown. And since I've had a root c, they said that I don't need novocaine. But I'm definitely they type of person who's afraid of dental work and the fact that they're going to be doing stuff in my gums really freaks me out. Has anyone ever had anything like this done before? Do you know anything that could help me out? Thanks in advance!