Today's feast doesn't mean that Mary is literally the mother of God, as if she is eternal like the Trinity. The title means that she carried within her womb the baby Jesus who was fully human and fully divine (the hypostatic union is for another day). Mary was the earthly mother of Jesus. Jesus needed to be cared for and loved and educated. It is in this sense that she is honored as the Mother of God.
I have to admit I didn't always "get" Mary. I knew I needed to know more about this woman called the Mother of God so while in grad school I took a semester long class on Marian Tradition. Sr. Carla Mae Streeter, O.P. started the first class by saying that she wanted to "kick the pedestal out from underneath Mary so that we can look her in the eye." That is exactly what happened.
I saw the young girl who proclaimed her joy-filled yes to the angel.
I saw the young girl who completely resigned herself to God.
I saw the young girl who marveled at the mystery of her cousin's miraculous pregnancy.
I saw the young girl who pondered so many things in her heart.
I saw the worried mother looking for her child in the throngs of Jerusalem
I saw the supportive mother who was the first teacher of her son and his first disciple.
I saw the distraught mother who watched her son and her Lord be beaten and murdered.
When you look someone in the eye, you can see into her soul. When I look into the eyes of Mary, I see someone who has far more faith than I do. I see someone who is far holier than I am. In the presence of such holiness, the natural response is to look down or look away because I am not holy. Mary trusted in the Lord completely and never relied on her own understanding (Proverbs 3:5). Mary deserves to be honored because of her faith and the example she sets for the rest of us.
Perhaps this is why Mary (and other saints) wound up on pedestals so that we can literally look up to our spiritual superheroes.