Let's talk about boobs..

Embarrassingly, I've always had pretty small boobs (like AA!) I've read so many things where women complain about how sore and how huge their boobs seem to be getting. Well, I'm currently 12 weeks pregnant and only have extremely sore and sensitive nipples, but I don't notice any growth. Is this normal? I'm afraid I'm gonna stay small throughout this entire pregnancy, and my biggest worry is that I won't be able to breast feed! Can anyone help please?