Mary is more than simply incidental in God's plan of salvation. She is instrumental.
God made Mary for this Moment. And her Yes was crucial for the redemption of the world.
All, of course, is grace.
from the Akathistos Hymn to the Blessed Virgin Mary
An Archangel was sent from heaven to greet the Mother of God, and as he saw you assuming a body at the sound of his bodiless voice, O Lord, he stood rapt in amazement and cried out to her in these words:
Hail, O you, through whom Joy will shine forth!
Hail, O you, through whom the curse will disappear!
Hail, O Restoration of the Fallen Adam!
Hail, O Redemption of the Tears of Eve!
Hail, O Peak above the reach of human thought!
Hail, O Depth even beyond the sight of angels!
Hail, O you who have become a Kingly Throne!
Hail, O you who carry Him Who Carries All!
Hail, O Star who manifest the Sun!
Hail, O Womb of the Divine Incarnation!
Hail, O you through whom creation is renewed!
Hail, O you through whom the Creator becomes a Babe!
Hail, O Bride and Maiden ever-pure!