Am I racist???????????

My friends all think I'm racist because I thought some people in my class were annoying and such. They were Mexican, but I am NOT RACIST AT ALL against Mexicans or any other race. I keep TELLING THE TRUTH but they're all like "Nooo you're racist :D". I DO NOT hate Mexicans at ALL, in fact, I know a lot of Mexican kids at my school who are really friendly and nice to me. I REALLY HATE THIS and I feel really hurt right now.......how can I convince them that I'm NOT RACIST and NEVER WAS RACIST?????