If it's making you uncomfortable, I'd talk about it. I doubt she's doing it on purpose. Though it's possible there's some countertransference going on, like maybe she's thinking of you in a maternal way. So she's subconsciously referring to her daughter.

As for whether it's appropriate for a T to talk about their own family, my T rarely does it, but my marriage counselor does it all the time, mainly to relate to something we're talking about. Though it can be difficult on occasion because I do have some paternal (and some erotic) transference for him. Like a couple months ago, he mentioned he was going on a trip with his daughter to look at colleges, like I think just the two of them, and I felt a twinge of jealousy. But definitely mention it.