I'm just trying to understand ok b/c the majority of Christians in the world call her Theotokos, and most i've spoke with interpret that as mother of God ok? When you say "she was the mother of the earthly messiah" your talking about Jesus, God Incarnate, in other words she was the mother of God Incarnate/Jesus/One of the trinity/ The Godman/ Jesus Christ. Right?
No God was not conceived by her in any shape or form. God has existed from eternity and that includes the Son. The Son existed BEFORE He entered through the working of the Holy Spirit into her womb. He is eternal. It was only His flesh which was conceived of Mary. She was NOT the mother of God. Think about it. GOD HAS NO MOTHER.
What she did was act as His mother while He was growing up. But she failed in her responsibility once or twice, and He repudiated her because of her attitude at least ONCE (Mark 3/21-35). He NEVER called her mother in the records we have. He called her 'woman'. Once He commenced His Messianic ministry He never called her mother. And He said quite clearly that those who heard the word of God and kept it were more blessed than she.