Hang around hole-in-the-wall used book stores! There are plenty of nerd girls, it's nerd guys that are hard to find. Have you any idea how hard it is to find a guy your own age who wants to discuss the validity of the dystopian future presented by George Orwell in 1984 versus that presented by Aldous Huxley in Brave New World?
im definitely a nerd girl, and a lot of times when i go out i wear a doctor who t-shirt or some kind of nerd-hinting article and i always hope someone will comment on it and I'll find a new nerd friend. search for nerd hinting clothing or accessories