What is a thing that makes you think “Wow, I’m really getting older”?

Talking to friends in their mid-20s and realizing that for them, 9/11 is something they’ve only read about in history books. They have no memory of it even if they were alive then.

A close friend of mine, her very first “world news” memory is of the second Iraq War in 2003. She was born in 1997.