What about the generally accepted idea that Mary was about 14 and Joseph was in his 30's? Not that they had sex, but that it was accepted n Culture and God's eyes for a 14 year old to be courted by a 30 something.
A 14-year-old girl was a legal adult in Jewish tradition--she was bat mitzvah'd at 12.
In
Romeo and Juliet, Lord Capulet thinks Juliet is too young to be married--she's not quite fourteen. But his wife thinks she
should be ready for marriage, because when
she was Juliet's age, Juliet had already been born. Lord Capulet, by contrast, was an old man. Shakespeare wrote
Romeo and Juliet in the early 1590s, and the ages of the two young lovers would not have raised any eyebrows in that society.
In Canada, the age of consent was 14 until 2008, when it was raised to 16, and in some provinces, it was still possible for a younger person to marry with parental consent (until 2015, when the minimum age for marriage was made 16 across the country).
So there's nothing odd about thinking that, theoretically, Mary could have been a married woman with children when she was 14. That was more or less the norm for the majority of human history. An adolescent girl was sexually mature, capable of having children, and didn't need a university degree and a career to have a fulfilling life. (Not that such was open to her--I daresay our present state of affairs is better in that respect.)