BTW, no part of my argument rests on the Douay-Rheims or the Latin Vulgate tranlsations. So if you want to get into an entended tussle about that, please direct your tussle towards some Vulgate scholar. That wouldn’t be me.
But your argument is resting on this translation.
Every catholic website I've seen uses this translation.
But, let's play along for a second and say this translation is ok.
It is still in the perfect tense and those rules of interpretation still apply.
Luke no where indicates Mary was filled with grace from her birth nor does this phrase Luke uses mean to be free from sin. Recall that Luke investigated everything he wrote about. He notes this in Luke 1:1-4.
No where in his account does he note, nor does any other author of the NT, note Mary was born sinless.
To be full of grace in the Luke account doesn't mean without sin. This is a blessing coming from God.
What we have is the angel Gabriel arriving at Mary and Joseph's house. He greets Mary and then tells her she has been "filled with grace"/"favored with grace".
In either case, that is the moment the clock starts ticking on Mary being favored/filled with grace from Luke's perspective. Not her birth.
Consider the following.
If Mary had been sinless from birth Paul writes a lie in Romans 3:23.
If Mary had been sinless from birth Paul writes a lie in Romans 5:12...therefore just as through one man sin entered into the world, and death through sin, and so death spread to all men, because all sinned.
If Mary had been sinless John writes in lie in 1 John 1:8.
If Mary had been sinless the writer of Hebrews writes a lie in Hebrews 10:12...but He, having offered one sacrifice for sins for all time, sat down at the right hand of God.
However Catholicism tells us (SUPREMI APOSTOLATUS OFFICIO ENCYCLICAL OF POPE LEO XIIION DEVOTION OF THE ROSARY)tells us that Mary occupies the highest summit in Heaven....not God...not Jesus....Mary.
If Mary had been sinless Paul writes a lie in 2 Corinthians 5:21...He made Him who knew no sin to be sin on our behalf so that we might become the righteousness of God in Him.
This smacks vaguely of MormonISM; when it's founder said; in Articles of Faith #8
We believe the Bible to be the word of God as far as it is translated correctly; we also believe the Book of Mormon to be the word of God.