It’s a dangerous thing to try to apply our 21st century ideas to people who lived centuries ago. Firstly, consider that the idea of having a “childhood” and “teenage years” as an extension of childhood is relatively recent. In the past children were not regarded in the way they are now. Consider that as recently as the early 1900s, children were expected to go out and do a full day’s work. I’m not saying this was a good thing, just that nobody had thought about this and done studies into human development and psychology that showed that this was bad. You’ll find that the Church, throughout the centuries, was generally quick to embrace new scientific discoveries and psychological developments, once they were well reasoned out. When the idea of childhood and the need for it, became recognised, obviously the Church affirmed the wisdom of this and changed its laws.Somewhat recently I’ve learned that the marriageable age for girls in the past, according to Canon Law, was 12. I’ve been trying to wriggle my way around this but it bothers me too much that the Church wouldn’t consider it a sin to take marry and take the virginity of a 12-year-old.
If you read Romeo and Juliet, you’ll see that Romeo was about 15/16 and Juliet was 14. The play gives a good idea of how marriageable age was viewed back then. Juliet was considered to be “maybe too young for marriage, but not quite”. And her father’s famous line was “younger than her are happy brides made” so we get the impression that this was just the norm at the time.