Must respectfully disagree

Throughout most of human history, in most cultures, intergenerational relationships were the rule, not the exception.

A boy began as a helper, then moved to an apprenticeship where he began to learn the rudiments of his craft, then began doing things on his own under the supervision of a master, then took his guild exam. If he passed it, he was considered a "passed master" and could travel the region, looking for work by the day (French jour) if necessary; hence our term journeyman.
It was years before he was established enough in his trade to support a family.

Girls who waited that long usually found themselves "out of the market"; it was quite the norm for a girl passing puberty to seek a husband who was capable of supporting her and her eventual children.

It was not unheard of for a girl to marry someone her own age, but she usually had to elope to do it.

Only a relatively advanced industrial society can afford late marriages and teenage celibacy.

In fact, girls and boys were not thrown together as they are today in school. The girls always had their parents looking for a suitable match for them, so they could move out and be a burden on someone else.
Naturally the parents wanted someone capable of supporting the girl.

There was a fascinating film called "Fiddler on the Roof" which deals with this quite extensively.