Perhaps it would be best to discard this word “grace” and use “unmerited favor” or something similar in its place. I should think this would make it much clearer what was being said.
Given that 'grace' is something given it would by definition mean prior to the giving a deity is not being discussed. I in no way mean to take anything away from Mary. Obviously she was appointed to be conceived and birthed to carry out her destiny at a specified time.
I am continually reminded of the instructions given to reverence no man... meaning to elevate a fellow brother/sister is akin to idolatry. But hey, my duty is to plant seeds of truth. Only God saves through His only Begotten Son. And He is the perfect judge.