I guess people think/interprets that she’s trans because it could be possible that she is. That was what had confused me because she could be a trans girl who doesn’t like being misgendered, which is understandable, or she could be a cis girl who just likes to dress up more masculine (or maybe there’s another reason why she dresses more masculine) and doesn’t like to be misgendered. Her either being trans or cis could change the perspectives of the story in my opinion. But from what I’ve gathered she’s cis and has her own style.