can't continue Daiana's story I keep having lunch with her in the afternoon and it won't advance I've done it like 100 times and never missed class
Not 100% sure, as my version probably isn't as up to date as this one, but I remember there was one character that this was the result with, and you couldn't advance the story no matter how many times you had lunch with her, and like you said, also never missed a class. And if it's the character I think it is, it's not only because no more content has been created/released, but also because she wanted to become "a good girl" and not be "easy/slutty" anymore, and the info in the game clearly stated that it was the end of her path, her storyline was complete. But like I said, my version is older, and it's been a long time since I've played this, so I could be completely wrong, and the name you said is (then) actually NOT that character I thought of. And I don't really remember character names from the game like that, not even the mom or sister's name, lol.