If you have kids, do you see them as less mature than how you perceived yourself at their age ?
TBH I feel the opposite: current kids have a lot more to deal with, and are expected to be much much more down to earth than a few decades ago. The most basic things: a single post on an SNS can stick with them for the rest of their life, yet we moved half of our social life online.
Not picking on your personal experience, but if you see it as a mistake, wouldn't it be a sign you weren't mature enough to take the right decision ?
Now, having a kid definitely accelerate that maturing process. But without a solid parental environment (which was common at some point, especially with the grand parents being around) it's a recipe for disaster, I wouldn't see it as an appropriate path for most in this day and age.
I see your point on much of a change it makes to have fewer young adults already being parents. That's definitely impacting.