I'm seeing this phrase (along with lady boss) crop up more and more recently.
My objections are firstly that I'm a woman, not a girl, thank you very much - as are all the women I've seen "girl boss" used in reference to.
Secondly, a man is never a "boy boss" or a "man boss" - he's just "the boss". Why does the female equivalent need a qualifier in front of it?
Thirdly, the whole phrase just has an offensive ring to it - as if a woman is doing a man's job. The word actress seems to be used far less these days and yet we're happy to use the term girl boss?
I'm sure it never used to be a thing - where has it come from and AIBU to hate it?