I've been thinking a lot about the "non-binary" definition.
It really is something that I dig, but there seems to be a problem in my mind.
From reading around, it looks like most of the non-binary folks are transgender and are seeking some kind of treatment, HRT and so on. But, unlike most transgender folks, they feel they are not totally male or female (which I guess is also the case for most cisgender people, anyway). That's also my case.
But if you're moving away from you biological sex, describing yourself as non-binary puts you in a grey zone, in the eyes of other people. This grey zone puts you somewhat closer to your birth sex than if you just describe yourself as FtM or MtF. And this can be a problem if you're transitioning. So I find it easier for me to think of myself as just a different kind of transgender girl.
Does this make sense?