Responses
Understandable. I think she's first mentioned in ch 9 or 10. Then the first time we see her in the manga is when the main characters come back from the double date trip by a river where Rin sprained her ankle. I think it was deliberate. Much as Yuki didn't notice Oushi's feelings, her presence was very much overlooked both figuratively and literally. They made her appear in the anime early tho.
Was I not paying attention where did this girl come from ???