Motherhood is a rum thing to begin with but motherhood in the mid-teens, in superconservative ancient Nazareth, engaged to a man you've never met and who is definitely not the father of the baby — well, then it would be time to hit the panic button, if only such a thing had existed.
But then, we're not talking about any young mother but the Mother — Mary — who has reigned from the uppermost throne of motherhood for over 2,000 years. Mid-teen or not, she embraced the whole incredible fate as hers, made a home with her husband Joseph and raised the baby Jesus — which, surprisingly, is a slice of biblical history that's largely been enshrouded in mystery.
Compared to what we know about her son, Mary is minute, considering her vast influence. Even cinema tended to circumvent the issue of her youth and the Annunciation, and when she has appeared (as in "The Passion of Christ") it's as the middle-aged mother of the grownup Jesus, who had to bear the terrible pain of watching her son die.