TBO,
True. But back then, the average "old age" was in the 50's with real old timers being rare. So therefore, if you weren't hitched by 12 (or 13, forgot which) then you were considered a spinster. By the time your kids got of age, you were most likely in your golden years at the age of 45.
If you really wish to get into history, upon the girls first menstrual cycle, they were considered women and of child production years and thus of marrying age, no matter if the girl was an early bloomer, or a late bloomer.
I don't know what year that the age of consent laws were created; all I do know is that the age of consent has been raised since the initial law was put into place, averaging out to around 16 to 18 today. Which makes no sense since the laws today don't entitle you to all adult "rights" until you are 21, in some states, 25.
It has also gotten to the point that the governments, local and federal, have closed the "loopholes" on men marrying child brides, as with Jerry Lee Lewis and Elvis, even with parental consent.
Wayne