Your past is just your past. In my opinion, it is what you let it be. You can choose to let your past control you and your future. Or you can choose to leave it behind as you move into the future. Your sexuality is what it is. You're attracted to whoever you like. The fact that you have experiences with guys in the past doesn't mean that you have to be attracted to them now. Or that those acts make you gay. If you like girls, then you can just continue liking them and enjoying them. You're straight and you like girls. That's that.
I understand why you're dwelling on your past and it's super normal. You have experiences which others don't. And those experiences are very real. They can't be undone and you have to live with the memories, unfortunately. But that's all that they are, memories. They do not define who you are or your sexuality. They're as powerful as you let them be. I know it happened long ago, but memories are still part of us. So it may help to talk to a therapist about what happened. It doesn't make you weak or crazy or anything. All it means is that you're ready to process your feelings about the past so you can move into the future without them. They can't be ignored, ignoring won't make them go away. So releasing them seems like the only way forward.
I'm kind of in your shoes. I had an uncle so similar stuff to me. And I know how hard it is to leave your past behind you. Those memories are strong, no matter how hard you try to leave them. But really, I know from experience that you can't ignore them. So it's time to instead try to process your feelings about it instead of letting it have this control over you.
Good luck and I reallyyyyy hope this helps you. :)
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kid, I wrote back,
all lovers betray.