I’m assuming that your question is not ‘How do I raise my child?’ but rather what is the impact of her current environment on her development?
Unfortunately for you, it is huge. As people, we like to pretend that we have more agency than we actually do. We like to picture ourselves as true arbiters of our destiny. We think that our beliefs are the result of long, drawn out philosophical wrestling and cold hard logic. These are largely lies that we tell ourselves to justify our beliefs. Largely, they come from social scripting and from social advantage. Not exclusively, I’m no determinist, but largely. In you daughter’s case, she believes herself to be bisexual. Why? Most likely, it began do to other people identifying themselves as such. She began playing with the identity and was socially reinforced by her peers. There is social gain with such an identification and she subconsciously weighs that gain with the social losses she may take. Similarly, her Catholic beliefs are likely bringing her a degree of social shame in an environment where upside-down crosses are apparently common place, so she experiments with distancing herself from them. It wouldn’t surprise me if at school, she is openly non-Catholic while at home she still says she is. Ultimately, it will be more than a shift in self-described identity and become a shift in belief. It’s fairly normal for us as a social species. The bottom line is that right now, she’s playing with her identity and while she may not be ‘naturally’ bisexual (whatever that means) it is likely that as she continually receives social reinforcement, her belief in who she is will change and she will believe herself to be bisexual which is really the exact same thing as being bisexual.
Of course, I will take a lot of flack for saying that because we have a predominant argument that sexual attraction is innate. I think though that we know for a fact that sexual attractiveness is extremely cultural. What we find sexually attractive maybe has some basic biological guidelines, but is heavily, heavily influenced by the culture around us. For instance, look up a painting of Philip the Handsome of Castile. I don’t want to be too much of a jerk about it, but he was rough, but at the time he was considered so handsome that they actually gave him the nickname ‘Handsome’. Similarly, we can look at artistic impressions of men and women throughout history that were famed for their beauty and frequently it makes us scratch our heads. It even happens within our own lifetime. Look at pictures of models from the 70s or 80s and at the time they were considered these ungodly paragons of beauty and now they just don’t have that same quality. Even looking at our own pictures from when we were younger, what we considered handsome or attractive we look at now and sometimes scratch our heads as to what we were thinking.
Anyway, we know that sexual attractiveness is largely cultural, but we like to draw lines at sexual orientation and I think that that line is arbitrary. We know that for instance it was considered normal during certain periods in ancient Greece for men to take on younger men as lovers. Does this mean that ancient Greeks were somehow latent homosexuals in incredibly huge numbers? I think that’s a reach. More likely, there was a social script that encouraged this particular sexual behavior and so it was simply normalized (We see a similar thing with the ‘child groupies’ on the west coast in the late 70s. Sex with barely pubescent girls became a normalized behavior within a subculture. This doesn’t mean that rock stars in the 70s were all somehow pedophiles or that young girls at the time were all sexually precocious, it was just socially scripted and they didn’t even consider why they were doing it.)
Anyway, to get back to my main point, beliefs are social. Whether you are Christian or atheist, whether you are a Trumpian or never-Trump, whether you are a vegan or a carnivore, an environmentalist or a drill, baby drill-er, and I would even go so far as to say many aspects of your sexuality (I wouldn’t go so far as to say your complete sexuality, biology is not destiny, but it’s certainly another part of the equation.) These beliefs are heavily, heavily influenced and perhaps even controlled by your social network. These beliefs can and do change throughout your life based on the social network you have (It’s why in college many people radically change their beliefs. It has nothing to do with education or maturation and everything to do with the fact that they have severed many ties to their old social networks and have developed completely new ones which forces a shifting of belief.) So to sum up, it wouldn’t surprise me if she believes herself to be bisexual because the people she is hanging out with say being bisexual is cool.
There’s the opening of a discussion, I look forward to being challenged on the specifics.