On the outside, Riley's a girl.
It didn't used to matter. Yeah, boy-kids have dangly bits that girl-kids don't, and she once got in trouble for an “I'll show you mine if you show me yours” dare that she'd done just out of curiosity (and why *she* got in trouble for it when *Nathan*, who'd suggested it in the first place, hadn't, was a sore point with her). But she knows the differences. Girls have boobs, boys have dicks, girls have to wear skirts and dresses, boys don't, girls are supposed to wear makeup, boys grow scraggly attempts at beards -- the older she gets, the more differences there are.
The older she gets, the less certain she is that she's a she.
She tries bringing it up once, in an offhand sort of way like it doesn't mean anything, with her mom. And her mom loves her, she knows, but her mom doesn't get it at all, and starts spouting nonsense about puberty and hormones and all that nonsense that Riley had read about ages ago on the Internet. So Riley shrugs and mutters something and slouches off, pretty sure that her mom isn't the place to go to get information.
The problem is, she doesn't feel like a girl -- despite all the outside bits, the boobs she'll grow eventually and the vagina and the various holes “down there”, the curves her mom promises she'll get someday and all the things no grown-up wants to talk about -- but she doesn't feel like a boy either. She doesn't want the stupid floppy genitals or the lump of an Adam's apple or the awkwardness of a cracking voice that some of the boys at school are going through.
And then one day she types “neither boy nor girl” into the search engine she uses (not Google, because she doesn't like the way they track searches, but something less well known but a lot safer) and opens about thirty tabs worth of stuff, and spends the entire weekend reading.
It's like things are clicking into place, snap snap snap.
The first and biggest revelation is that it's not just a matter of boy versus girl. That she can be both, or neither, or something else entirely. That there's a whole spectrum of possibilities.
She eats when mom or dad calls her down, but it's all in a distracted sort of daze, and she gets back to her room as quickly as possible. Reading. Digesting. Thinking.
It all makes so much sense that it feels unreal,
And when she finds a forum for people like her, and posts a first hesitant post -- hi, my name is Riley, and I think I'm agender -- the response she gets, welcoming and affirmation and support, feels somehow like coming home.