Teehee, I think we all have a wee bit of OCD in us, just some of us are a little more obsessive than others
I wouldn't worry too much, I sometimes freak out that Maya has to do things a certain way or for example when we drive past the New Lynn train station she has to say "I'm scared of Nikki falling on the train tracks" not once but three times every time, I think I am more aware of it coz I have OCD myself. But I think kids just do it to exert control, they don't have a lot of control over their environment so they exercise it where they can ie. by lining up the shoes.
For what it's worth, I wasn't particularly obsessive as a child or even as a teenager, I've kind of grown into it