In Catholic teaching and theology, there is what is called a vocation1, i.e. a calling. From all eternity, God has called each one of us to be what he wanted each one of us to be. This calling is unique and unrepeatable precisely because each person is unique and unrepeatable2.
1. We define personal vocation as God's call and plan for one's entire life. cf. GERMAIN GRISEZ ON PERSONAL VOCATIONS | EWTN.
2. cf. b. Unique and unrepeatable | B. OPENNESS TO TRANSCENDENCE AND UNIQUENESS OF THE PERSON in COMPENDIUM OF THE SOCIAL DOCTRINE OF THE CHURCH.
The following sample biblical passages are offered in support:
23 He said to them, “You will drink my cup, but to sit at my right
hand and at my left is not mine to grant, but it is for those for whom
it has been prepared by my Father.”
16 You did not choose me, but I chose you and appointed you that you
should go and bear fruit and that your fruit should abide; so that
whatever you ask the Father in my name, he may give it to you.
43 But now thus says the Lord, he who created you, O Jacob, he who
formed you, O Israel: “Fear not, for I have redeemed you; I have
called you by name, you are mine.
Thus Mary was God's choice to be his Mother and now is the only choice because she said yes! And we thank God and her for that.
What could God have done if Mary had said no?
With God all things are possible3. In Catholic teaching and theology there are infinite number of ways by which God could have accomplished the redemption. We thank the LORD and his Mother for having agreed to be the New Adam and Eve.
3. cf. Matt 19:26
Please see: CCC 490ff.
What was the calling of Eve, what was her glory?
She was the first woman, the mother of all living, among her children, Mary the Mother of God, and her Son, the Son of man4.
I am sure Eve is not complaining.
4. cf. Matt 8:20.