I don't think those of us who are 21 are Xers. I'm not sure what we are. My parents were probably Xers, or on the cusp. Certainly they're not Boomers.
definition of genX
The young ones are being tagged with
You're right, 21 is NOT Generation X
2 - 22 Generation Y
22 - 42 Generation X
42 - 58 Baby Boomers