Not for nothing, but she was supposedly gestating a child that was immaculately conceived, thus no sex was had... thus, not really related to sexual contact with minors.
"The Immaculate Conception should not be confused with the perpetual virginity of Mary or the virgin birth of Jesus; it refers to the conception of Mary by her mother, Saint Anne."
I don't think so, at least not if they actually read the New Testament. I remember very little of it, but I do remember it mentioning that Joseph did not 'know' her until after she gave birth. Pretty sure that means they didn't wait another 5 years to consummate their marriage.
So marrying at 13 is fine as long as you don’t consummate the marriage until you’re 18? I haven’t met many Christians who feel that way. Most of the time, the rationale is ’those were different times, it was normal then’.
https://en.wikipedia.org/wiki/Immaculate_Conception
"The Immaculate Conception should not be confused with the perpetual virginity of Mary or the virgin birth of Jesus; it refers to the conception of Mary by her mother, Saint Anne."