I've had the opposite happen. At the time, I was 35, and I was taking my foster son, who was 16, to buy a suit for a formal dance. We went to the counter and he put the suit down and I paid for it. And the clerk gave us a really confused look the entire time. She finally said, "are you like, just a really nice big brother, or...?" He said, "no that's my foster dad." And she kind of looked relieved and said, "ohhhhh I was gonna say you clearly weren't old enough to be his birth father." But like... I was though. Also that was an incredibly weird thing to think, let alone say.

Also for context, I look a bit younger when my face is shaved. But I had a beard at the time, gray patches and all.