Moses penned Genesis and in particular 3:15 in Hebrew not the Vulgate. So the reference would go back to that Hebrew language. Genesis 3:15 "it" i.e. Christ not a flesh being that would 'bruise' thy head. IF one reads this verse as written in the Hebrew one will know exactly what the sin was that cause Adam and Eve to figure out they were naked and covered up themselves with 'fig' leaves.
That had nothing to do with the word “she”.