There’s nothing in the Bible that gives us marries age. It does say she was a virgin, and that word is sometimes translated as young woman. The main reason she is generally assumed to be very young is that the custom of the day married women off at a very young age.
But, her cousin being older might indicate she was older. It’s possible she was unattractive and undesirable physically, but quite compelling spiritually.
The Bible in Isaiah says about Jesus appearance that he had no form nor comeliness that we should desire him. In other words he wasn’t built and he wasn’t handsome.
If the Apple doesn’t fall far from the tree, then an unattractive man might very well have unattractive parents. It’s comforting in a way to think that it’s what Jesus was saying and doing that made him such an attraction. It wasn’t how he looked
These are all just my own thoughts. Others might know more, and have better opinions
He may not have been handsome but I seriously doubt someone could grow up skilled as a carpenter in that day and age and not have some kind of physique.
Don't forget, it's the same guy who made a whip of cords and threw the money changers from the Temple, and after being almost beaten to death at the whipping post, still managed to carry His own cross for part of the distance.