I think that's a close enough guess. Back then "girl" meant child regardless of gender. A male child was a "knave girl" and a female child was a "gay girl". The word "boy" was used when referring to servants.The term "knave" signifies the medieval period and was usually applied to male persons of doubtful reputatation, but connected to the word "girl" the only guess that I can make is it may refer to a male youthful person.

I'll go for Shining Tor at 559 metres/1834 feet high.