Is it okay to be in the school library?

Well, it might just be because I'm having a bad day, but nearly every day of the year I go in the library with some of my friends. On the way home on the bus this hideous girl kept calling me a nerd, and that I was friends with these really nerdy people who I barely even know. Boy was she such a hideous skank, and she's a year younger than me. When I was getting off, she said 'Bye, Nerd!" and I just said 'bye'. But i felt like saying "Bye, you dumb-A.S.S h.o.e" but im too nice to say that. So... is it okay to be in the school library nearly every day at lunch break?