What’s the likeliness?

Husband and I had a baby three (almost 4) months ago, in the spur of the moment he finished in me. I’m not on birth control. We always say if we got pregnant it would not be the end of the world but we’ve been pulling out each time, aside from this single time.

I’m not beating ourselves up over this, we are adults and would welcome a baby if that were to happen but I’m wondering the likeliness of it because I am breastfeeding and still have not had my period since having our son. Thanks :)