Mary kept all these things to herself, holding them dear, deep within herself.
Luke 2:19 (from The Message Bible)

Every mother has high hopes for her baby from the minute he or she is born. What will he grow up to be? Who will she look like? Will he be smart? Will she be popular? A million questions run through every mother’s head when she sees her newborn baby. Mary had the same questions, and one more that we wouldn’t ask. What will happen to the Son of God?
If you have read the entire Bible or have never opened one, if you’re in church every weekend or just for funerals and weddings, you still have heard the story, you know how this baby’s life on this earth ends. Unless you have lived your whole life under a rock somewhere, you know that the baby Jesus grows up, shares the truth about His Father, and dies an unimaginably painful death on a cross.

Imagine that you are Mary or Joseph and you could see your baby’s future and know that horrible end? How could you have any joy in your life? Believe it or not, God knew the horrible end His son would face and still He sent His son to us, so that we would not have to face that pain ourselves.