Thoughts on dads showering with daughters

Hello! We're expecting our first daughter in April and tonight my husband asked me, "what am I supposed to say when one day she asks me daddy what is that, should we stop"?  Haha I laughed and thought if they did shower together it'd be when she was young enough and wouldn't remember. But when is she too old? Maybe when she starts to understand? Wanted to get yalls thoughts and how you handle this situation. Even with boys with moms too.