"she couldnt have had any stain of sin as Christ couldnt have been carried in the womb of a sinner."
I'm no theology expert but how it was explained to me differs a bit from what you express.
Is it true that Christ "couldn't" have been carried in the womb of a sinner - I have my doubts as nothing is impossible with God.
I once heard the explanation that Christ did this for Mary out of great love for His mother (honor thy father and thy mother) - and also as fulfillment of Genesis - one interpretation being that the "enmity" between the woman and the serpent was fulfilled in Mary. The "enmity" referring to sinlessness, and also creating a "new Adam and new Eve" as we can see referenced to in early christian writings.
Where Eve disobeyed...Mary obeyed.
Were Eve befriended the serpent - Mary was never placed under the dominion of satan.
This doesn't make Mary a goddess...this places her in the original human state prior to the fall.