The church celebrates when Mary said, "yes" and God became a man.
I was discussing this with our friend Father Nathan one day. I said something like, "God is so all powerful that He could have done it a different way. He didn't HAVE to bring God to earth through a woman." Father Nathan's response was something like, "But THIS is what He chose to do. Who are we to think that there could/should have been a different or a better way." I understand that THIS is why the Catholic church boasts of her HONORING Mary and her "yes" to God. Not just because God could have done it another way and this is a nice gesture on the part of a nice lady, but that GOD DID CHOOSE to bring God to earth in the way. His plans far out weigh ours, do they not?
And the added bonus of today is that even though it is lent, it falls on a Friday and is a solemnity, so even in the middle of Lent, we get to celebrate! And celebrate I will... with a nap!