The notion that IF Mary was sinless, she did not need grace, or a Savior, is absolutely baseless.
Mary’s sinlessness was a result of grace. It was the result of the saving death of Jesus Christ.
She is not noted as being sinless in the Word....anywhere.
catholic encyclopedia online tells us there is no direct proof found in Scripture for this false teaching.
The word grace used in this passage in Luke is used in one other place in the Bible and that is Ephesians 1 where Paul is us that with this same grace, God has blessed us (believers) in the Beloved. IOW, we all have access to that grace and it has been bestowed on us all.
http://biblehub.com/greek/5487.htm
Luke 1:28 And he came to her and said, Greetings, O favored one, the Lord is with you!
Ephesians 1:4-6 In love he predestined us for adoption as sons through Jesus Christ, according to the purpose of his will, to the praise of his glorious grace, with which he has blessed us in the Beloved.
Greek word grace
charitoó: to make graceful, endow with grace
Original Word: χαριτόω
Part of Speech: Verb
Transliteration: charitoó
Phonetic Spelling: (khar-ee-to'-o)
Short Definition: I favor, bestow freely on
Definition: I favor, bestow freely on.
HELPS Word-studies
Cognate: 5487 xaritóō (from 5486 /xárisma, "grace," see there) properly, highly-favored because receptive to God's grace. 5487 (xaritóō) is used twice in the NT (Lk 1:28 and Eph 1:6), both times of God extending Himself to freely bestow grace (favor).
Word Origin: from charis
Definition: to make graceful, endow with grace
NASB Translation: favored (1), freely bestowed (1).
Now stay alert for a second or two while I show you something about your reasoning ...
You have (rightly) taken something from a later time frame and applied it to an earlier time frame (Grace to Mary is sourced from a later event in her son's lifetime). God has ALL of Time open before Him at all times.
Now apply that same reasoning to what Elizabeth said when she spoke of 'the Mother of her Lord'. The Lordship could just as easily be understood as sourced from an event which had not yet occurred in Elizabeth's timeline but which is absolutely going to happen because it is God's plan of Grace!
The Word pre-existed even the worlds of the Universe. That Word came into a human person named Jesus of Nazareth, as ALWAYS the plan of God. You have zero evidence to support that Presence was present during the gestation of the body of Jesus, but you have assumed it in a way specious to the Plan of God since the Word of God says 'You are my Son, This day have I begotten thee'. The Mormons take that phrase to me God had intimate relations with Mary, to conceive Jesus in her womb. A blasphemous assertion we would both agree.
So, apply the TRUTH that a thing already is if God plans it, even if it has not yet occurred on the Earth's timeline ... 'he rejoiced to see My day' should be a big clue for us!
The reason I conjecture you will reject this offering to you is because it removes one of the duplicitous positions of catholiciism which allows raising Mary to a status The Word does not show us.
So she WAS a SINNER before she recieived grace; RIGHT?