[TheRealPomax]

That's quite an assumption to make about when someone had kids.

[war1025]

It's ballpark accurate though, right?

[jiveturkey]

eh? not at all. the mean age for a first child is now 29.

https://www.cbs.nl/en-gb/news/2019/19/average-age-of-first-t...

and

https://www.cbs.nl/en-gb/figures/detail/37744eng

the latter has underlying data for which you can extract %ile parent age. To save you the time, by parent age 40 it's under 10%ile.