From Youngs LITERAL Greek translation
Luk 1:28 And the messenger having come in unto her, said, `Hail, favoured one, the Lord [is] with thee; blessed [art] thou among women;'
charitoō
This is NOT A NOUN describing someone..it is a VERB..an action
1) to make graceful
a) charming, lovely, agreeable
2) to peruse with grace, compass with favour
3) to honour with blessings
Grace is not a liquid like gas that we fill a tank with.. it is Gods unearned favor..
God had favored her with the blessing of being the mother of my Savior.. she was blessed..
There is not one thing anywhere to suggest she was sinless...
why would God have used a stained vessel to bear His son??