Life is like good food: you'll want all ingredients properly mixed in at the right time (with some added randomness and creativity). Trying to eat the ingredients one by one in some order that you think will make the food better is almost guaranteed to disappoint.
This is entirely self-centered. The kids, instead, benefit immensely from having parents with experience, emotional maturity, financial stability, better work-life balance.
You might not get to meet your grand[grand]kids but this is a sacrifice parents should be willing to make to provide a good life to their kids.
For men, it's really not, until they are 40+, and if in good health, even 50.
Biology unfortunately or fortunately requires women to have healthy kids until a certain age, and the more women are aware of it the better for them (that is if they plan on having any)
The other thing I've realized being old: if you're going to have kids, have them young. There is absolutely nothing on this earth which is as valuable as the time you'll have with your children. I've waited until late in life to have kids, and it strikes me now that it means I might not ever get to meet my grandkids. I'll have decades less time with my kids to pass on advice and support them. I think if there's anything I'd trade my youth for, it's spending time raising kids. I'd gladly work a few hard years in my 40s and 50s for that privilege.