This kinda looks like DumbKoala style but with animation.
Did they have lolis in the middle ages
...
I mean girls were having babies at 12 because you only lived to 30 -35 at the most.
Common misconception, average lifespan was low mostly because of high infant mortality not because adults were dying young.
If you survived childhood you had a fairly standard life expectancy.
Other negative factors included death during childbirth, death via violence, death via diseases, death via starvation.
No one was dropping dead at 40 due to old age!
Young pregnancies are a different matter, there wasn't any tv so you need to do something to pass the time.
Although due to higher calorie access during development at the present time you would be more likely to be able to get pregnant younger now than in the past on average.