For context, I'm a bisexual, polyamorous, cis woman. That frame of reference impacts how I answer this.
I think Mo hits the nail on the head with the "queer" label being a nice catch-all, if you feel comfortable with that. I have friends who joke that because they are trans/non-binary, every relationship they're in is gay
. As for your attraction to different varieties of humans, I'd like to point out that there are all sorts of different kinds of attraction. You say you don't know if you can picture yourself in a relationship with a girl, but think you might still be attracted to women. That's fine! Maybe you're aesthetically attracted to women, or maybe you're sexually (but not romantically) attracted to them. I have a friend who is asexual, but experiences romantic attraction. On the flip side, I have a long term friend with benefits who is not interested in romantic attraction at all, but rather prefers to have several friends that she has sex with. You don't have to be equally interested in all genders in the same way in order to identify as bisexual or pansexual. Also, your partners or lack thereof don't define your sexual orientation, so it's not like you need to be with both a man and a woman to be bisexual. Here's a grid I like better for human attraction than the traditional three point scale of "gay-bi-straight": https://imgur.com/hPuGKes
As for being poly, some people think of it as an orientation, some people think of it as a lifestyle choice. I personally feel like it's a bit of both. What is true is that opening up a relationship looks different for everyone, and it is absolutely essential to have open lines of communication and trust with whoever is involved. You say that you are like the idea of polyamory "just as much" as monogamy- that's fine! Those are just boundaries you will need to discuss with whoever your partner is. If you want to read good books on the subject, I highly recommend Opening Up by Tristan Taormino, or The Ethical Slut by Dossie Easton and Janet Hardy.
Hope that helps, and happy exploring!