It depends on context, but when we are talking about the competence of people to do a professional's job, then yes, girl might suggest that any competence they have is precocity, they are not mature and well-rounded, and they are not generally what you want the pay grade above where they are.

And girl/boy are not quite analogous. "Boy" can be used in a belittling way, but it more often used in phrases like "one of the boys" to mean easy-going and fun: a positive statement about someone's ability to work in groups.

It's not an easy point: there's a few women I know who think that not using "girl" means that you think they are too old to be attractive. I think that often holds in both the US and the UK; it used to be true here in Germany, but I think calling a woman "Maedchen" in her workplace today is positively offensive.

I advise you not to call female colleagues girls in the office, and be sensitive outside the office. It's a good topic to raise in conversation.

To be clearer, I was more taking issue with original comment's blanket rule that adult women can never be called girls. As you said, "It depends on context", and I think the original comment neglects this.

I'm totally aware it's not always appropriate to use such terms.

Absolutely. Well, as a male, if someone calls me a boy I consider it belittling. I'm pushing 30 now, so it doesn't bother me so much, but when I was in my early 20's it definitely seemed like code for "inexperienced idiot".

She didn't use boy/girl interchangeably. She used girl/man.