Nonsense. Every human with the exception of Adam, Eve and Christ Himself was conceived in sin.
This is why Mary needed grace just as every human does. She herself in Luke 2 called God her Savior because she humbly knew that she also was in a sinful condition and needed salvation from it.
Your comment:”Nonsense. Every human with the exception of Adam, Eve and Christ Himself was conceived in sin.”
Who made you God? and all knowing? You offer no justification for your statement.
There are well written explantions of the Catholic Church teachings on this subject.
I can’t believe that you call Jesus a sinner.
Just hypothetically, if you were to know God did will, through His divine providence, to create a woman free of original sin, so as to be a worthy mother for his Son, what would your reaction be? Praise to God for his power? Hope that we may one day be like the woman?
Suppose that Son of the woman, as one of his last acts while dying on the cross for our sins, gave her to the members of His church to be their own mother, just as we were to be His brothers. Would you love the woman as your own mother?