It is important to distinguish between the use of a word that is a cognate or homophone of a modern term, and the use of a word that is a synonym to a modern term. What I mean by this is, using the word "girl" in a certain time period would not have been the same as referring to a person as "a girl" in the modern sense of being female child.

Girl (girle, gerle, gurle) came out of Middle English in the 1300s, and was a gender neutral term for a child of either sex. The word boy also stemmed from Middle English, but was associated with being a male servant, rather than a male child. Henry VIII, if he was ever called "girl," would have been on the fading end of such usage, as the "female child" meaning had started to show around 1375, more than a hundred years before his birth in 1491. I wouldn't call it impossible, though.

Source: Webster's Dictionary of Word Origins

For what it's worth (and same source as above), "man" got its start in Old English as a wholly gender-neutral word as well, meaning any person, or humanity in general. The word for a male adult was "wer" (whence comes the first half of "werewolf") and the word for a female adult was "wif" (whence comes "wife"). The modern "woman" stemmed from combining "wif" with "man" as "wifman" with a functional meaning of "female adult person," as a means to distinguish meaning after "wif" started having the sense of a "wife" we now use.