Where else and about whom else is this written in Scripture?
There is nothing in Scripture that says that being full of grace equates to sinlessness.
Wrong again. You'd think that after having been exposed for being such a poor student of Scripture, you'd stop sticking your foot in your mouth. However, you are indeed a glutton for punishment.
"And the Word was made flesh, and dwelt among us, (and we saw His glory, the glory as it were of the only begotten of the Father,) full of grace and truth." John 1:14
"I will put enmities between thee and the woman, and thy seed and her seed: she shall crush thy head, and thou shalt lie in wait for her heel." Genesis 3:15
"And the angel being come in, said unto her: Hail, full of grace, the Lord is with thee: blessed art thou among women." Luke 1:28
You don't help your cause by quoting mistranslations of Scripture.
It's *HE shall crush your head and thou shalt bruise HIS heel.* It's talking about Jesus, the sinless one who conquered death and brought mankind redemption.
Grace does not equate to sinlessness. Show me the Greek translation and definition that says grace means sinless.