Imagine you would (be a heterosexual man, in case you are not, and) wake up next to your bombshell, blood related sister, while you're both in your teens, and she's just wearing a shirt and maybe some panties. I on my part imagine, this would be bigger than just, "Meh. It kinda happens." I mean, that should be addressed. "Seriously sis. Let us talk about what just happened. What the fuck..."
Welp, rotten girl is best girl, but she also doesn't deserve to make the cut. Not because of her fetish, but because she is cucking herself. He is was there, he is was simply for the taking, but she didn't do it. And now all that stuff happened with other girls, which should be of more of concern for her, but she isn't even really jealous? I'm under the impression, she wants to be in a relationship with him. Even though she scored some real good points there, she took her words back, because she was embarrassed? I get they are teens. But I also get, that some other girl, whom he is important enough to, to confess, should be with him. If there is no harem ending, that is.