I'm a girl, so I don't get quite as much crap for loving ponies. However, I'm also the kind of girl who wears a lot of black, doesn't do a whole lot of smiling away from my friends and has a very dry, sracastic sense of humor. So people are just kinda like, "Wtf?!" I'm used to it though. I've always loved Disneys movies, musicals and such despite my "dark" appearance.
Honestly though, only about three people know of my pony love. My two best friends and the brony who introduced me to it. I don't exactly hide it, but I don't advertise either. If it's on my screen, I leave it there. No matter who walks by. I have sketches in my sketchbook and I have friends that ask to look through it, which I don't mind.
So, I don't hide it, but I don't talk about it much aside from with other bronies. I really want to get tshirts and other merch though! Then I'll be about 20% cooler.