In giving birth you kept your virginity; in your Dormition you did not leave the world, O Mother of God, but were joined to the source of Life. You conceived the living God and, by your prayers, will deliver our souls from death. 507
Catechism number 973
By pronouncing her "fiat" at the Annunciation and giving her consent to the Incarnation, Mary was al ready collaborating with the whole work her Son was to accomplish. She is mother wherever he is Savior and head of the Mystical Body.