Because the age of consent laws changed. Here’s the background.

In western law, the age of consent is the age at which an individual is treated as capable of consenting to sexual activity. Consequently, any one who has sex with an underage individual, regardless of the circumstances, is guilty of a crime. Narrowly concerned with sexual violence, and with girls, originally, since the 19th century the age of consent has occupied a central place in debates over the nature of childhood, adolescence, and adulthood, and been drawn into campaigns against prostitution and child marriage, struggles to achieve gender and sexual equality, and the response to teenage pregnancy. This module traces the shifting ways that the law has been defined, debated and deployed worldwide and from the Middle Ages to the present.

An age of consent statute first appeared in secular law in 1275 in England as part of the rape law. The statute, Westminster 1, made it a misdemeanor to "ravish" a "maiden within age," whether with or without her consent. The phrase "within age" was interpreted by jurist Sir Edward Coke as meaning the age of marriage, which at the time was 12 years of age.

A 1576 law making it a felony to "unlawfully and carnally know and abuse any woman child under the age of 10 years" was generally interpreted as creating more severe punishments when girls were under 10 years old while retaining the lesser punishment for acts with 10- and 11-year-old girls. Jurist Sir Matthew Hale argued that the age of consent applied to 10- and 11-year-old girls, but most of England's North American colonies adopted the younger age. A small group of Italian and German states that introduced an age of consent in the 16th century also employed 12 years.