The mums are the time keepers

LOL - a generation is defined as 40 years not 25 so its more like only 50 women since 1AD

That’s a common misconception both about marrying age and life expectancy. Average life expectancy was so low in the past because infant mortality was so high, but if you made it to 18 you could reasonably expect to make it to 80. Second, marrying age was in their twenties for most people, some teenage weddings did happen with royalty, and even some child weddings, but those were the exception not the rule. In the US, the decade with the lowest marrying age was the 1950’s.