I had a professor in grad school who was 65 when his 40-year-old wife had a baby.

Kid's 10 now and chances of the good prof being around to see him graduate from college are slim.

Mid-30s is a pretty decent time -- most people are pretty well settled by then in finances and careers. I wasn't one of them, of course, LOL so don't go by me! But I can tell you for sure that the older you get, the less energy you have, so it's kind of a tradeoff. Like pretty much everything else in life.