TGL, it is heresy to state that Mary was the mother of God (specifically that term), or to call her the Virgin Mary, considering that she is no longer a virgin. You can call her Mary, mother of Jesus.
Those terms are Catholic heresies, and have no place on this board. Please stop using them immediately.
And actually, I don’t think people are lost just for not believing in the virgin birth. It’s kind of part and parcel of the story of salvation, but they have believe that Jesus Christ died for their sins,, and was raised again, according to the scripture as well. But you have a point that it’s good to learn from all the people in the Bible, and not to exclude her.