Koiwai's experience in love is warped not just because of a storybook it seems, but also because she decided to become simply an observer. She doesn't want to hurt people because she's fascinated with love.
Now that's she a target of love though, she's using her own thoughts about love to pursue Shunsuke with no breaks! She doesn't even know if she really loves him yet!
But it seems Shunsuke himself has put some breaks into Koiwai's desires. Going to the summer festival is something that he does with Hinaki, and it seems he's not willing to go with just Koiwai...