The New Covenant God ushered into existence was not with through Mary but through the Man Christ Jesus, who without an earthly father, did not carry the sin nature of all born of Adam (including Mary). Covenants, in the past were made with the blood of bulls, goats and sheep...but the New Covenant was in the Sinless Blood of Jesus Christ, the LAMB OF GOD WHO TAKES AWAY THE SIN OF THE WORLD the ONLY SAVIOUR.
Careful that you don't deny that God entered the world through Mary.