This side of eternity, growth in grace and in the knowledge of our Lord and Savior Jesus Christ is possible. I have dear Christian friends who do a little Mariolatry on the side. I have other dear Christian friends who do a little Unitarianism on the side, and send their kids to public school. Those who know me best can, no doubt, point out inconsistencies in my life and faith. But, I trust they still love me in our common Lord.
There's something in fallen human nature that loves the idea of alternate feminine channels to God's grace. This is, perhaps, an artifact of the original sin, when Adam stood by and watched Eve argue with the tempter, and then accepted the fruit from her hand, and ate of it. He received, from the woman's hand, a perceived short cut to "the knowledge of good and evil," and godlike status.
Veneration of Mary has its root quite simply in her being among the central characters of the Gospel and central to the mystery of the Incarnation. If it makes you feel better psychologizing it away, I guess, that would only be consistent with your lack of interest in the scripture. As a Calvinist, you’d rather deal with philosophical speculation, no?