As a Protestant I was taught growing up that all of this Mary "stuff" was a late addition to, or more precisely a degeneration from, a true "Biblical" Faith.
According to this reading of history Constantine converted, and the downward slide began from there. The Church became a big evil organization, and the Dark Ages descended. In those Dark Ages Mary began to be worshipped and adored with the reverence which belongs only to the Triune God.
Here is a wonderful excerpt from Justin Martyr, who died in 165 A.D., written less than sixty years after the death of the last Apostle. Note the exalted position already given to the Mother of God even at this early date.
True, there has been development and change in the veneration of Mary over the many centuries of the Church's existence. But, like every great teaching of the Church, the seed was there from the very beginning.
Behind Justin Martyr stand the Scriptures themselves,
beside Christ at Cana encouraging His vocation,
mourning at the foot of the Cross with young John as Mother of All Disciples,
crowned finally in the book of Revelation with a place of pre-eminent honor,
yet submitted fully to Her Son who is to rule the world.
She is the new Eve.
She is the God-Bearer.
She is the Spoiler of Satan' power.
"We realize that Jesus became man through the Blessed Virgin, and the disobedience caused by the snake ended in the same way in which it had begun.
Indeed, Eve, virgin and intact, conceived of the snake’s words and gave birth to disobedience and death; the Blessed Virgin Mary conceived of faith and joy when the Angel Gabriel announced to her that the Spirit of the Lord would come upon her and that the virtue of the Almighty would cover her with His shadow, so that the Holy One conceived in her womb would be the Son of God.
And Mary answered: “Let it happen to me as you have said.” Therefore Mary gave birth to the Child foretold in the Holy Scriptures… By Him, God ruins the snake’s empire as well as that of angels or any people who choose to resemble the snake. God frees from death all those who repent from their sins and believe in Him."
P. S. Tomorrow is St. Justin Martyr's Feast Day. So you'll be reading more from him tomorrow. Meanwhile, I'll close this special Feast Day with a prayer in the Spirit of the Day for Our Lady.... it expresses a true faith in God and our Mother Mary: