there are also individual differences about how open and transparent people are about themselves on any personal matter. some people are just more private and less disclosing about themselves than others. perhaps you have a higher need for privacy than your daughter? perhaps you have a different boundary about what is private and what is public information? this can complicate matters that impact you both. she may be ready to come out to everyone, but you may not want to tell everyone your daughter is bisexual.
it’s important that parents put their children first. she could easily perceive your hesitancy in sharing as an indication that you are embarrassed or ashamed of her.
now to address your specific worries:
it’s not real, but more of a peer pressure thing. imagine declaring something as important as your sexual orientation and your parents didn’t believe you. since you don’t care one way or the other, back her up. if she is fluid and changes up what she is reporting to you — just go with the flow and let her know that you love her no matter what and thank her for the update.
that maybe girls feel safer declaring that they don’t like boys because it allows them to negotiate these difficult relationships with less fear. there has been a lot of research on this topic that i suggest you dig into. there are certainly unchangeable biological factors, as well as social factors in understanding and expressing our sexual orientation. different people have different journeys, but none should be dismissed as “you were just going through a phase,” or you are “just feeling safer with women.” this still carries an implied message that is belittling to their reality. keep talking to adults in the lgbtq2+ community and hear their stories. find parenting groups online and in social media and keep learning and supporting one another together.