Can't say anything about this as "Toots" and I first had sex when she was 15 and I was 18. We were married the following year, had our first kid that year, too!
I do have to say though, it was pretty much the norm in the parts of the country we were from.
37 years later, it seemed to work for us. Divorce in our families is a four letter word! Not so with today's society, where you can drop your spouse because they snore!