I don't know the nuances of this, but it seems to me that there's no particular reason for Kayleigh to wait for final grades, or even for the exams, if she doesn't want to. Her classmates didn't wait for exams or grades. The fact is, she's already entered the portal and is on the way to some other destination, whether it's been determined yet or not. If she's really nervous about her grades, I can see taking one's time about deciding on the destination school. But this would be a problem for her even if she somehow decided to stay at USC. I think athletic scholarships come with a minimum grade requirement even apart from questions about portal rules. I think it's a 2.3 GPA. I'd be really surprised if grades are an issue for her. She seems like a smart focused kid.
What all this says to me is that she's taking her time, maybe because of grade anxiety, maybe because she's simply frazzled by the end of semester noise, maybe she's the type of kid who likes to get all her ducks in a row (classic PG-style thinking), or maybe she just wants to spend a few days at home with her parents after the exams are over to talk it all out.
If by any chance she's already made up her mind, I suspect Geno already knows what she's going to decide. Probably Niele and Shea do too. I doubt any of them would pull a Mulkey and try to force her hand with a premature hint. But maybe she hasn't made up her mind. Who knows?