Alas, Steepholm, this may be your first time, but it won't be the last. Just wait till some well-meaning teen at the counter offers you a pensioner discount when you're working full time and earning twice what he/she is. Or stands politely for you on public transport. It is particularly saddening when you used to get asked for proof of age when going to a film over PG rating, or offered a child discount when you're 28...

On the other hand, I was once walking on the street with my seven-year-old great-niece when a lady asked if she was my daughter because she looked so like me. "Niece," I said. I didn't have to go into detail. ;-)