I suppose it's normal enough. I don't get that thing some people have with feet, but I really like socks. If all she wants you for is your feet, that's not normal at all. But if she loves your feet AND the rest of you, then it's all good.
Almost as good as socks. I really dig socks. Not in a sexy way, I just like them. You can do all sorts of things with socks: Get them wet and stick them to the wall, dust your computer and wax your car, clean up spills, or put them over your hand and have a cool puppet. They come in all different colours and textures, and are warm and cozy. You can put them almost anywhere and they'll fit, and combined with 2 rolls of quarters they make a formidable weapon. You can't do all that with a girlfriend, by the way. Socks rule!
But your girlfriend sounds normal enough. And you can probably get a foot massage any time you want, which is a bit of an added bonus. Can I borrow some socks?