Was i right to have gotten upset/annoyed?

I was with my baby in a creche last week, (I had a meeting in the building next door), and when I returned to get her after the meeting, the play worker or whatever you callthem these days, came up to me saying "did you know your daughter growls?" I was quite taken aback, she persisted with it and I said well thats on eof her ways of communicating, she is only 4 months old. I have been thinking about it ever since and I have worried myself so much that I cant stop thinking about it. I will also be taking my daughter there again this week, its at our local family centre where I do a bit of volunteering. Is this growling noise normal? I would have thought that her working there and presumably educated to do so, she would know about communication, development, ect? What do you all think? Thanks in advance!x