After some review, I think Moriyama was talking about a college entrance exam for Uchida, not the final exam. The finals wouldn't be scheduled so late, especially for the graduating seniors, so it was probably the entrance exam specifically for the college she was aiming for. In Japan, most kids take the Center exam that most public and private universities use for their admission decisions, but many schools have their own exams. Also, Uchida was aiming to be a teacher so it wouldn't make sense that she would barely pass high school. I'll fix it soon.