Some are actually dating Gen Y much further back, calling the cutoff in 1993 or 1994. Others are calling the cutoff as 9/11. Most are inbetween.
Many are calling the cutoff for your generation as 1993 or 1994 because the defining event is 9/11 and some feel that, in order for someone to be in Gen Y, they would have to have some memory of the event.
http://en.wikipedia.org/wiki/New_Silent_Generation(Silent Generation-beginning anywhere from 1993 to 9/12/2001,depending on the generational scholar.)
I've read more and more recently on the subject. Many seem to be calling the cutoff mark as 1994.
Remember, it could always be worse. I'm a Gen X'er. We don't get much respect from anyone.
(Another argument is that the late 80's and early 90's is it's own generation.
http://en.wikipedia.org/wiki/IGeneration )