The age that the average person has kids is indicative of the general quality of life in an era, and that's been the case throughout history. People waiting so long they're infertile from old age indicates that today life is particularly hard despite being better off in material terms than most other times in history thanks to the advance of technology.

If things were as good as the elites tell us they are, then it would be common to have 45 year old grandmothers, since 21 isn't really an unrealistic time to be married and pregnant if you're not terrified about whether you can feed another mouth and lose an earner in the household.