Why is Gen Z so obsessed with generations?

I often hear so many of these statements from Gen Z on tiktok and this sub like:

“ blanks are the last year to have a real childhood” “Older gen Z are these years ___” “Blanks are the last valid years” (whatever that means)

And much more! And not hating but so curious on why specifically we are so obsessed with making sure our birth year is included in the older generation and almost like proving ourselves that we’re not to be associated with years younger then us. I even remember having Facebook and this being a discussion like 10 years ago. Millennials seem to be just as obsessed as well, but theirs comes from a sense of pride that they are millennials.