I didn't even know what a furry was while in high school, and I didn't became a furry until February 18th, 2011, which was eight months after I graduated high school.
I also found out my best friend from high school was a furry, but unfortunately it was after we graduated.
Besides him, though, I don't really know if my high school had any furs since I didn't really know about furry until after I graduated. And I didn't even have the slightest clue to what it was until April 2010, when I was a Senior.