Sex with no protection but avoiding pregnancy

So me and my husband have been having sex for months now using no protection and I'm not on birth control btw, but he does pull out. I am very educated on everything and very familiar with the statistics and all that. I'm just being weird maybe but wouldn't I get pregnant off of precum by now or something? I hear all these story's off these teenage girls getting pregnant off of precum. I feel like I'm not fertile or my husband isn't. Idk maybe I'm being crazy. Any answers for me lady's?