I would also say the cut off is in 1997 (gen z starts here) because of the technology aspect. The 9/11 is such an American way and doesn’t apply to e.g. my country of origin. We heard it in the news but that was it, no effect or anything.
For us, the Balkan war was much more significant in life, where we could separate our generations better. But the technology aspect is a worldwide criterion, that fits better to divide a whole (worldwide) generation. If you just want to divide American generations than 9/11 is a good criterion.
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