Maternity clothes

I'm about 18 weeks along in the pregnancy, and I'm not wearing maternity clothes yet. Part of me wants to be, but another part of me knows that if I was, I would only get bigger. I have bought mostly tops and a friend is letting me borrow a few things. I'm going shopping on Wednesday with a friend to look at some maternity stores that I haven't been to yet. Maybe in the next month it will be time to wear them.