That's odd, I thought Shinobu taught at university level, but in chapter 4 her students are wearing school uniforms. They don't wear uniforms like that in Japanese universities, do they?
If i remember correctly, I thinks it's because she teaches a cram school or something. cause she was talking about how she didn't want to tell the students whom she meets only two times a week.... I may be wrong. She might be teaching at both. who knows. :D