Yes, in the sense that I am also shy and being around people who are the opposite of shy make me a little nervous. I'm not used to people being that outgoing and have long since learnt that I don't get along all that well with them. I can handle them as friends that I see once every so often but the last person I almost got into a relationship with was absolutely not a shy person and that was part of the reason I ended up being like "ok i can't do this". He would've been the kind of person who wanted to go out and meet people, do lots of things, and so on. That's not the kind of lifestyle I want, so I definitely want someone on the shyer scale of things.
However, since I am shy and am already a little hindered by it, I'm not all that attracted to anyone who's even shyer than me. I mean, I don't want to be the one who always has to go ask for extra napkins or make all the phone calls because the other one is too shy to do it! :P I'd rather be the one whining until the other one does it. So while I do prefer shy people, I don't think I would ever be all that attracted to someone who was as shy as (or shyer) than me.