I mean I am AFAB and I do identify as a girl but also I don’t feel entirely binary. I guess I wasn’t assigned Nonbinary at birth but it still feels weird to say I’m trans when I’m AFAB and present and act like and call myself a girl. I don’t know, help me out here people.
The right answer is whatever feels correct to you.
Personally, I have thought of it like a scale from 0:1, with all the possibilities between them being trans and the endpoints being the two binary genders. However, the more gender theory you read, the less helpful that seems.
I believe Forrest Valkai said that Biology is moving towards the idea that gender is a spectrum. So your thought seems to mirror that.