I think what made a huge difference for me was knowing other non-binary people in person. I knew that non-binary was a thing, but I’d never questioned my own gender that seriously. And it’s not like the media is full of genderqueer characters running around. In my mind, if I didn’t experience horrific body dysphoria, I was cis[gender]. But then in uni I had friends who were trans and non-binary, friends who casually used they/them pronouns. And eventually I started thinking about it and figured out that “oh yeah, I’m not a girl”.
Genderqueer was the first term to resonate with me, though now I use non-binary more – they’re both umbrella terms, really, but I don’t feel the need to look for a more specific label. There’s a lot of labels whose definitions do apply to how I feel about my gender – maverique, greygender, genderfluid, genderqueer, sometimes agender. But I don’t know that one of them necessarily covers it all, and I’m never 100% sure about the various facets of my gender identity, so I feel much more comfortable with plain ol’ NB. It gets the point across.