Currently in my Sophomore year, and a fairly new furry, so I haven't gotten much time to sniff out others in my school. ;b
Most of my close friends know I'm a fur (they're some cool people; glad to know them) and occasionally they'll poke fun at me but it's never anything serious.
I don't wear anything like ears, a tail, or a collar because my school has a pretty strict dress code and there's plenty of students who'd never shut up about it if I tried to, so I'm pretty discrete with my furriness(well, not counting my sketchbook xD).
I was actually really surprised when I was talking to a guy who sits behind me in my German class and during conversation he looked around before whispering that he's a furry. I was really happy to find out I'm friends with another fur
I'm sure there's more in my school somewhere; I mean we have 3,000+ students so it's highly possible.