How old are you? I was quite sure that I wouldn't have kids, either, but I randomly met a nice girl who lived in the (urban) apartment upstairs from me and next thing I knew, I was 38, married, and watching my son being born. It comes at you fast and unexpected and it wasn't at all the life-ruining thing that I was sure it was when I was 28. Here in my early 40s, my only regret is not doing it earlier.