if someone is a cis girl who is romantically attracted to girls and nonbinary people is she considered biromantic? or does biromantic just refer to being attracted to the binary genders?
biromantic describes anyone of any gender who is romantically attracted to two or more genders, be those genders binary or not, so yes. biromantic would totally describe the person in question.
it’s also worth mentioning that although biromantic is more commonly used, polyromantic– ie. romantic attraction to multiple (but not necessarily all) genders– could also describe the person in question.
which term a person uses ultimately comes down to personal preference.