Historical fact. In early Victorian times it was legal for girls to marry aged 12. This was changed to 16 later in the Victorian era (1884)
Today it is still legal for a girl of 16 to marry, provided she has the consent of a parent or guardian. A woman aged 18 can marry without parental consent.
Some unsavoury things went on in Victorian England.

Indeed Opti, all the way back as well.
In medieval times in Nobel born or regal circles some girls under 10 were betrothed and married, but only had children after puberty and their first period. These are some interesting facts often also involving the politics between ruling families and keeping the strength of their line:
+ In 1396, Richard II of England was joined in marriage to young Isabel of France, who had been 7 years old when their engagement was announced the previous year in Paris.
+ Bianca of Savoy, Duchess of Milan was married aged 13yo (1350), and aged 14yo when she gave birth to her eldest son, Giangaleazzo (1351).
+ Theodora Comnena was aged 13yo when she was married King Baldwin III of Jerusalem (1158)
+ Agnes of France was 12yo when, widowed, she was married to Andronicus Comnenus, Byzantine Emperor (1182).
+ St Elizabeth of Portugal was aged 12yo when she was married to King Denis of Portugal and gave birth to three children shortly thereafter.
+ Caterina Sforza was betrothed aged 9yo, married aged 14yo, and gave birth aged 15yo.
+ Lucrezia Borgia was married to her first husband aged 13yo and bore a son within a few years.
+ Beatrice d'Este was betrothed aged 5yo and married aged 15yo.
We must never forget that this was all happening in the context of the time. Like for a woman could be very short, maybe living to 35 - 40 years but many dying a lot earlier in childbirth or from the many fatal illnesses around at the time.
In Nobel and Regal circles there was tremendous pressure to produce heirs, especially males (Henry VIII is a prime example of that situation!) before the woman became too old and baron, or died in early childbirth.
A young woman was considered most fertile in her early tender years and needed to be mated with as early as possible, within of course a marriage.
All this history of course NEVER gives any man the right to touch sexually "a child, a minor", as we live in very different days with woman now often opting to have, and being able to have, babies into their forties. Life expectancy is of course also vastly different with many of today's young looking forward to a life reaching 100 years of age, barring war and human self destruction from other means!!