Picture a girl with her arms full of small packages, too many to hold all at once. When they topple and fall all around her, she stoops down and scoops them all back up, literally re-collecting all the gifts that are already hers. To set your mind is to recollect truth that already belongs to you.
There is no activity that is somehow more Christian than another. God looks at the heart, and that is the good part that Mary knew. he simply asks us to come as we are and to be willing, open to receive whatever he might have for us this day. That is what it means to live a graceful life.