God did not force or compel her. And that is the more astonishing, that God would choose a lowly Jewish girl betrothed to a Jewish man in order to cometh in the flesh to this world to save us who are doomed without His Grace and Mercy.
My mother was impregnated by a rape, yet she had such love and fear of the Lord that she brought me forth anyway, as her third child. It is indeed a power pro-life message that Mary chose the rigors of child bearing instead of rejecting the Holy One of God. Any woman or girl pregnant with another living human being should take a lead from Mary's bowed head.
So... God is not sovereign?
To imply that we can, in some way, decline God's will for our lives (as in some way to "refuse" salvation) is to make God someone WE can in some way control or influence; God would no longer be... God.
John 6:
37All that the Father gives me will come to me, and whoever comes to me I will never cast out. 38For I have come down from heaven, not to do my own will but the will of him who sent me. 39And this is the will of him who sent me, that I should lose nothing of all that he has given me, but raise it up on the last day. 40For this is the will of my Father, that everyone who looks on the Son and believes in him should have eternal life, and I will raise him up on the last day.”
And later...
44No one can come to me unless the Father who sent me draws him. And I will raise him up on the last day
we really cannot say how it is that God knew Mary would bow her head and say 'thank you, Lord; be it unto me according to God's will.'
Actually, we really can: it was God's will for her. God is sovereign. He is omnipotent, omniscient, omnipresent and eternal. If not, he's not God.
No doubt, Mary favored; Gabriel said so. But, because God CHOSE her, it would BE her.
Hoss
Any choosing that went on 2000 some years ago was by JOSEPH!
He 'chose' not to divorce her!