Agab

The signup form on their website did not have a non-binary option, so I had to select my AGAB instead.

Source: wiktionary

Since I came out to myself, I felt myself stop dressing in the way I thought I was "supposed" to dress based on my assigned gender at birth (AGAB). […] It can still be scary to dress in a way that doesn't match what I was taught based on my AGAB, but it's also really empowering to embrace who I truly am and share it with everyone.

Source: wiktionary

Genderfluid people can question themselves, worrying that they're "supposed to transition" or that they're "regressing" if they present as their AGAB, or that they're a fraud if one of their gender forms happens to be their AGAB. Accepting genderfluidity, however, means accepting how many forms one's gender can take.

Source: wiktionary

Your AGAB is the gender that you were assigned at birth based on what your doctor and parents decided you were due to the shape of your genitals. […] The term transgender […] was originally used for people who are transitioning to a presentation different from the one associated with their AGAB. It is used more broadly now to refer to people who do not identify with their gender assigned at birth, whether they were assigned male and know that they are female, assigned female and know their gender to be fluid and flowing, or any combination thereof.

Source: wiktionary