No one is born in sin because of their own actions, but because of the actions of Adam and Eve. And I can find no Scriptural basis to support the idea that Mary was born without sin. To say that Mary was born without sin and was without sin throughout her life would be to undermine the whole point of the Cross - that humans cannot be sinless, and it took the sacrifice of a perfect Lamb (Christ) to wash away our sins. If God would take away Mary's original sin, why wouldn't He do it for all - after all, God is not a respecter of persons.
Sorry, you certainly have the right to believe as you wish, but I can't buy it. When I see people praying to Mary and to "saints", that crosses over into idolatry for me, and I can't go there.
Perhaps a metaphor will help. If we look at man’s sinful life as falling into a hole, and Christ’s Salvation as lifting him out, then think of Christ saving Mary from falling into the hole in the first place. In both cases, Christ is the Savior. In Mary’s case it takes place at her conception, in our case, after.
It’s not perfect, but that’s my understanding.
Why would God take away Mary’s sin at the time of conception and not others? I understand why this would be a puzzler for you and seem to contradict Christ’s atoning sacrifice on the Cross. Yet to me there is no contradiction. For although Christ’s death redeemed us and overcame the penalty of death and opened the door of heaven to us it is still the Grace of God that saves us. And grace is an unmerited gift which God dispenses according to His will not ours. In fact the declaration of the Doctrine of The Immaculate Conception states
“...by a singular privilege and grace of the omnipotent God, in consideration of the merits of Jesus Christ, the Savior of mankind, ...”
It is also easier to understand the teaching if you have an appreciation of Mary being seen as the New Eve and as the new ark of the covenant bearing the living Word. It was not fitting that the living Word be carried in an unclean, corrupt woman.
Also their is Scriptural support for the dogma (and you certainly are free not to interpert it so) the Greek term for “full of grace” is Kecharitomene. As explained in an article about the Immaculate Conception
“The expression (Greek kecharitomene) in the angel’s salutation, represents a proper name, and must on this account express a characteristic quality of Mary. The principal reason why the pleasure of God rests in special fashion on her is her election to the dignity of the Mother of God (Theotokos). Accordingly, Mary’s endowment with grace proceeding from God’s pleasure must also be of unique perfect. However, it is perfect only if it be perfect not only intensively but also extensively, that is, if it extends over her whole life, beginning with her entry into the world.”
A further discussion on the term can be found at
http://www.philvaz.com/apologetics/a116.htm
“” ‘Highly favoured’ (kecharitomene). Perfect passive participle of charitoo and means endowed with grace (charis), enriched with grace as in Ephesians 1:6 . . . The Vulgate gratiae plena [full of grace] “is right, if it means ‘full of grace which thou hast received’; wrong, if it means ‘full of grace which thou hast to bestow’ “ (A.T. Robertson, Word Pictures in the New Testament, p. 14)”
“However, Luke 1:28 uses a special conjugated form of “charitoo.” It uses “kecharitomene,” while Ephesians 1:6 uses “echaritosen,” which is a different form of the verb “charitoo.” Echaritosen means “he graced” (or bestowed grace). Echaritosen signifies a momentary action, an action brought to pass (Blass and DeBrunner, Greek Grammar of the New Testament, p. 166). Whereas, Kecharitomene, the perfect passive participle, shows a completeness with a permanent result. Kecharitomene denotes continuance of a completed action (H. W. Smyth, Greek Grammar [Harvard Univ Press, 1968], p. 108-109, sec 1852:b; also Blass and DeBrunner, p. 175).”
So there is Scriptural basis for the teaching. But I understand your objections and certainly don’t see it as something it is essential for Non Catholics to believe. Though I assume most believe Mary was without personal sin even if they believe she to was born with original sin.