How Am I Supposed to Know if I'm Trans

I'm 14 and have been identifying as nonbinary for a few months now. I have not told my parents, but my friends call me by he/they pronouns. Whenever someone calls me she or uses really any term for females on me I get really irritable I guess. There's like an ache in my chest. I also physically can't imagine myself in a male body... Like I want to but I just don't see it. I've been in the same body for so long it's weird. I look good right now, too. Idk I don't know what to do and I'm confused. I've also started to question if I'm actually just a guy and not nonbinary. I don't know, though. I don't know any older trans people and really just need guidance. I hope I explained this well enough.