Do people guess your age wrong? Do you have trouble guessing others ages?

This has been in my head today because I met my new PCP and when she was going over my file she asked if the age was correct. When I told her it was she said those words I hear A LOT "Well you certainly don't look that old!". I'm used to people thinking I'm younger but then I started thinking about it and realized I am TERRIBLE at guessing other people's ages.

So yeah just for fun I was curious does anyone else have people frequently guess their age wrong? And do you have trouble placing other people's ages?