It’s certainly also a cultural phenomenon. Most young people in their teens and twenties in the West do not want to start a family at a young age, and not only for economic reasons. It’s a priority to enjoy a lifestyle that’s not compatible with raising children or a marital commitment.
I don't think culturally it's changed to much -- around the mid-to-late twenties is still when most people want to settle down, get married, and have kids.
Of the people in this age range that I know, the more well-off they are the more likely they are currently married and having kids. Those that aren't well-off are not enjoying a lifestyle because they can't afford that either.
I thought this, but part of me wonders if life maybe would have been better having kids at 20.i met someone who was 30 with basically independent kids. And then in your 30s and 40s you actually have money to enjoy the world with. Your also still pretty fit in your 30s, maybe not the peak of your fitness but it's not like we're all going pro at sports.
I had kids both in my early 20s and again in my 30s and being a younger parent was better. You have more of a social life, you have more energy, you aren't as worried about things. I had way less money and lots of things were a struggle but then those were all the best memories. Now money is less of a problem and time is more of a problem.
I think it depends on the person. My 30s were my most fun decade, and I can't imagine doing much of what I did if I'd had kids then. I knew a few people who'd had kids in their early 20s (and one even earlier), but I barely ever saw them during that 30s time period.
I'm in my early/mid 40s now; if I'd had kids in my early 20s I suppose they'd be college-age now, and I'd just be getting back to a more-or-less child-free social life. (Granted, that would depend on all my friends also having done the same thing.)
But I don't have kids at all, and, frankly, I don't have the energy to do much of the stuff I did 10 years ago. If I'd spent the last ~20 years raising kids I imagine I'd have even less energy than I do now.
But at the same time I can't imagine having a newborn now, or even in the past 5 years or so. That sounds beyond exhausting, and I'm not sure I'd be able to do it.
I bet that’s partially it. A lot of people don’t want to use their youth to raise kids, they want to use it to have fun. Nature however intended us to do differently.
