I have a different hair type than most of the posters on this thread, but I wear my hair very short. In my case, my hair turned out curlier after I chopped it off. So what? I don't understand why everyone keeps bringing that up as if it's a negative thing. Your hair might be curlier, it might look almost straight depending on your hair type. But, as long as you get a good cut with a good shape, it will look great.

I think you should go ahead and do it. It's only hair, and you can always grow it back out if you don't like it. Since your hair is already bob-length, it won't take long at all to get it back to to there if you don't like your pixie cut.