I don't get the distinctions between sport fans, fangirls and art/literature/culture aficionados either. I started with ballet when I was 5 years old, which is kind of both sport and culture, and had no problem drifting into theatre for a while, then discovering fandom and the joys of academic literature discourse at the same time when I entered university. I've always brought the same core of passion and intensity to everything, and it never felt much different in the end.

No, you probably won't change their minds, but you'll get the rant, squee, whatever is bugging you, out of your chest. When I am with friends, that is often reason enough for me to do it, so that it's out there and not festering or souring in my mind. It's different with acquaintances, colleagues, and family. Like you, I don't talk about it, or keep it brief. Why bother if I don't need to and they won't get it, anyway?