I’m not who you were responding to, but first borns certainly aren’t necessary. High fertility, low marriage age places like West Africa meet the 15-20 range pretty spot on. A woman can easily have a child every year or so from 15 to 20, then they sort of coast to a stop by their late 20s. The majority of births are early because their so close together.
I have personally met 30-year old grandmothers who didn’t think anything of it. They’re 75% of the way to average life expectancy anyways.
I would say an average of 5 mothers per century up to 1850 or 1900 sounds about right, and is still a fairly conservative figure.
Pre-modern first-birth ages were more in the range 15 to 20. So rather 5 to 6 mothers per century.
You’re assuming that your matrilineal line is entirely composed of firstborns.
I’m not who you were responding to, but first borns certainly aren’t necessary. High fertility, low marriage age places like West Africa meet the 15-20 range pretty spot on. A woman can easily have a child every year or so from 15 to 20, then they sort of coast to a stop by their late 20s. The majority of births are early because their so close together.
I have personally met 30-year old grandmothers who didn’t think anything of it. They’re 75% of the way to average life expectancy anyways.
I would say an average of 5 mothers per century up to 1850 or 1900 sounds about right, and is still a fairly conservative figure.
And the meme is being conservative