it's normal curiousity and "bragging about what she knows" my daughter used to say that, or somewhere she heard someone ask "where is your husband?" and was going around asking EVERYONE she passed (mainly family) some got offended and yelled at me behind her back-aunt that never married-couldn't get past someone from her past, no husband no kids, some said, "you need to get her to stop that" (mom) and some just gently told her the truth (great aunts who's husbands have passed on)
so in the car one day, i told her that question is really between her and mommy because it's not a question you ask just anyone without knowing them first.
i didn't want to embarass her or make her think she can't ask questions but i wanted her to know that some questions are meant to be between mommy and her. she asked if she should apologize, i told her no, you're learning, and that's what counts
so maybe just gently explain some questions or "what i know" are meant to stay between mommy/daddy and baby
but don't make a huge deal about it....it's cute