The ages of Mary and Joseph aren’t named in the Bible.
However, there are several people names as Jesus’ brothers and sisters. Scholars tend to go “Mary married Joseph” so half-brothers / half-sisters make sense. However, the Catholics HATED this notion. It also led to the Merovingian heresy which tracked the descendants of Mary, destined to rule and ultimately to give birth to a reborn Jesus-. So official church doctrine maintained that any brothers and sisters must have been from Joseph’s previous (and thoroughly unmentioned and never referenced) marriage to someone else.
That would make Joseph older than Mary, in their fanfic reasoning. And since in the context of kings and the Roman Empire, powerful older men chose young, child-bearing women…
Now I’d be remiss if I didn’t say I’ve also been searching through various Christian sites. They don’t mention explicitly the ages. Then they immediately go on to justify Mary’s statuatory rape/pedophilia. Mainly through their own interpretations. (A) “well, gosh gee willikers, it’s just what happened at the time”. And/or (b) “there’s some (sus) older scriptures that had nothing to do with Mary that prove we are right”.
For example (of the sus), the apocryphal Book of James, written around the Second Century. It was most likely created as a response to other proto-Christian sects. In it, Joseph was elderly and Mary was 12. He never had sex with her which was the point of the book: Mary was “ever-pure”.
As far as the non-apocryphal Bible, there are portions of it that date far before the Roman Emperors. The Council of Nicea in the 4th Century made sure to stitch together one of the forms of it and they definitely altered things for a political narrative.
The earliest gospels, though, come from about 80 years after Jesus’ death. None of them provided references to Mary or Joseph’s age or purity, other than that Jesus had brothers and sisters and that Mary appeared at a wedding that Joseph didn’t. This might imply that Joseph died. Or busy. Or they didn’t invite him. Plenty of room for interpretation because–big surprise–they were focusing on the Jesus and not the Joseph.
tl;dr Mary’s prolly not a teenage, unless you’re a Catholic and then ew.