This is, I think, at the heart of the mystery of the intercession of the saints and especially of Mary. God does not refuse her, as they say, because she does not ask anything outside His will, since by grace she was able and willing to make a complete self-offering, and God accepted the offering He enabled.
When we pray, "Thy will be done," there is often only a sort of formal and half-hearted (if that much) offering of our wills to God. Still, we believe that in His will is our peace and we long and pray for the grace to make that petition with utter sincerity, holding back nothing. In the meantime we are not astonished when our prayers are not answered as we would like, because we know that much of what we think we want does not accord with His will.
If we think of Mary or any saint sort of cajoling God into changing His mind, well, then there is some merit in the objections. When Mary is described as sneaking into heaven through the back door those who would not be granted admittance through the front door, well that's worse than merely silly.
But we who pray to her for her prayers nonetheless often have an astonished sense that something good is happening in us, despite ourselves.
You would think that the Calvinists and we could share some happiness in the shared perception that God acts in us despite ourselves.
But maybe that's not as fun as fighting.
You're darn right she's special.
However, she is not worthy to be praised, nor prayed to. She was still a sinner, same as you and me. For all have sinned and fall short of God's glory.