I didn't choose to have kids, but I have a friend who prioritized doing so, and she talked about hoping to have a larger family. She got married and had her first child not long after graduating from college. So biologically a very healthy age.

She ended up with two. Pregnancy sounds nice and well until your teeth start falling out. Some women just have a really rough time of it - so doing it while also being the primary caregiver for 1 or more other young child... yeah, even if you're financially stable and supported from your spouse's job, that is really a hard thing to manage.

In her case, it seems extra hard because neither her parents nor her husband's have helped with caring for the kids.

Meanwhile, my step-sister (who is less financially well-off than my friend) has 3, but they are constantly hanging out at my parents place or with extended family. Having nearby family that wants to help makes such a huge difference.