I have never had that strong, overwhelming urge to be a mother. I knew it was something I wanted to do though. My DH and I were solid and had been together a long time, so it just felt like it was the natural next step to start a family.
I am grateful that I was able to choose to have a child when I was ready. That wasn't until I turned 30.
I stopped at one child for a myriad of reasons, but deep down I really just don't have that strong urge to have another baby. I would actually seriously consider adopting a daughter if it wasn't such a difficult process. It's mostly pregnancy that I just don't want to chance again.