Exploring one's sexual orientation. The process of it

If you're part of the community, you could think back to how you felt when you were finding out and how you accepted yourself. If you're not, then you could talk to folks you know who are - particularly those who have had a hard time accepting themselves.

Honestly, for me, I can barely remember when I was realizing. I just got a crush on a girl in 7th grade, got awkward and dumb inside my head, talked about it with my family, and that was that. But my parents are accepting, so I didn't have that obstacle that your character has. There will probably be friction with her against her parents. I honestly think the process of finding out is drastically different for each person - and the same thing goes for how people go about accepting themselves. But if you've just discovered that you like girls and you're a girl, and you're working your way to accepting yourself, then... you'd probably do a lot of things. You might take online quizzes ("Am I really this way? No, I can't be... What does this quiz say?"), or talk to people around you who are out and proud themselves to get their advice/opinions on things ("This person seems to have it all figured out. Can they help me piece together what I'm missing when it comes to accepting myself?"), or research stuff online, depending on the reason that you don't accept yourself (like if it's religion, then you might find yourself looking up existential theories), or search up famous LGBT people and learning about their journeys. There are other things too, obviously. Coming to terms with something like that in yourself just takes a lot of time and important conversations (even if these conversations are with yourself). You just need time to think things through, try out things that scare you, and talk to people who can help you figure things out.

Another random thing I just thought of is the 5 stages of grief - yes, it's not the same thing, but I don't know, I'm going to attempt to relate it to your story scenario based on what I know:

Denial (No. I'm not a lesbian. I wasn't attracted to that girl, I just... admired her. I wanted to be her friend. I was hot because it was sunny outside. I was tingly because I'd been sitting down for a while and my blood wasn't in my limbs. And I was horny because I'm just in that age range, and hormones are like that. Yeah, maybe I'm fine with it affecting my friends, but with me, just no. It makes no sense. I've always liked boys, and I'm supposed to like boys. My parents want me to like boys, and they've always known what's best for me, and they're adults so they just know stuff. Okay?)

Anger (Okay, maybe all of this furious denying isn't actually doing anything. It's such bullshit. Why me? What caused this realization to happen so suddenly? And if I'm so okay with it in terms of my friends, how come I can't give myself a break? What's up with my parents?)

Bargaining (Alright, [insert name of something she might want to bargain with {I'm kinda thinking of a higher power right now, so if she isn't religious then this might not be helpful}]. I'm not gay. If you stop this crap by tomorrow night, then I'll help out my homeroom teacher after school. Please, just give me a crush on a guy. I know that you can - that I can do it. If you do this for me, I'll... I'll do anything.)

Depression (Shit, this is really starting to scare me... Nothing is working. I couldn't stop thinking of that girl last night. And when I was changing in the locker room for PE, I was so red and I felt like I was going to explode, just trying to keep my head down. I'm starting to get envious of my queer friends. They're going out and doing things, exploring themselves, being happy. I think I'm stuck. I don't know what to do. Maybe I just need to accept it. But no, my parents would never... screw my parents. Maybe? Oh, god...)

Acceptance (Wow. This is fine. Ha! This is totally fine. There's nothing wrong with me. This is beautiful. I don't need to like guys. Girls are great. I think I can do this.)

Not sure if this helps, but those are my thoughts. I also know it's not the cleanest answer. I'm actually writing something with a similar element. But my character's internalized homophobia comes from her heavily Christian father. For her, there are scenes where she does sexual things with a girl, and all the while she's screaming at herself in her head (things her father has said, Bible quotes, etc). She ends up moving fast and hard, checking out of the moment in a way, to stop herself from flipping out in the middle of it. She has cognitive dissonance going on; like, she knows that logically it should be okay, but she just can't shake the internal voice that says it's twisted and wrong.

I hope you have fun writing your story. I like the idea you have :)