9/11 isn’t the real flashpoint, but it’s a good mark for an individual person. People born in 98 have much more in common with people born in 03 than with people born in 93.

Not remembering 9/11 means they don’t remember a time before the war on terror. They were aware for 2008, but only vaguely, depending on how affected their parents were. Millennials were entering the workforce. And yes 2016 was the real defining year for Zoomers, which if you were born in 97/98 was also the year you graduated high school, the oldest Zoomers.

The biggest “general vibes” difference as I can think to put it is that Millennials were told that if they did everything right they had a bright future ahead and it was dashed, while Zoomers have never known a US that wasn’t already in terminal decline, and have never had much hope of a better future.