Good question

Millennials are defined as anyone 12-30 today.  That does limit the Gen Xers a bit I guess.  It's clear that those under 12 or so are also in a different category.  They don't remember not having DVDs or cell phones.  So they're not just totally at home with technology, they don't know it is technology but rather an extension of themselves.  Gen Y is what we now call Millennials.  It's just a little more defined now.

As for the largest generation in history, that was true but you all had 2.4 kids.  America has also grown a lot, with so many millions who don't come from families that lived here in WWII.