The Millenial Generation

I've learned today that km is from the Millenial or the Y generation. So is my wife, is that legal?
I texted km saying "You don't look millenial."
"Thanks," she texts. Hmmm. Sarcasm.
"I don't know what it means to be millenial. Shouldn't you be shiny or something?"
"I am shiny. Duh," she texts. Millenials all think they're shiny, duh.