Anonymous girl, if you ever think in silicon I suggest not to do it. In long term goal, silicon will make your body ugly, and even in short time the size of the tits breaks the natural proportion in your body. Besides that I have already met really attractive pretty girls who weren't even a C cup size. When you meet the right guy in your life who really likes your body, including your tits, the way they are, you will not think about it. So don't worry, just do what you need to do to have a healthy body then you can express all the natural beauty your body was projected to.
Let me put this into an equation, where (S) is the size of boobs, and (H) is hot.
(S)2=H. Basically, what the equation is saying is that size of boobs (S), times 2 (because most people have two breasts) = Hot (H), unless SDD. That is the case unless you go to the opposite ends of the spectrum (completely flat, or so big, you can't hug the girl). Some guys like those though, so it really just depends on the guy. So, for me (and most guys, presumably) the equation, (X)2=H is an accurate representation of my (our?) opinion on breasts.
@Anonymous I love them personally. I did a question about whether men notice small breasts more then larger breast. I'm not sure if that's something strikes interest, but figured I'd mention it. I got some really great answers from men and women. Anyways you're welcome to check it out on my profile.