If Mary had no sin, she did not need a Savior.
However, if she experienced God's grace, that means conclusively, that she was a sinner as only sinners can experience grace. Grace only kicks in in the presence of sin.
Romans 5:20 Now the law came in to increase the trespass, but where sin increased, grace abounded all the more,
If she were sinless, she would not be *favored* by God, she would be getting what she deserved, which is NOT grace, it's justice.
I would stop feeding the troll.....