"Are you a middle school student?"
I also put あなたは中学生ですか and had it marked wrong.
I find it very frustrating that the Japanese course is much less flexible than the other language courses I am taking in the range of different answers it accepts.
This means that even though I know the answers to all of the questions (I lived in Japan for several years, and am really just doing this course for fun), I find myself using the flashcards rather than just free typing most of the time, because the course is likely to reject many of my answers even though they are actually correct.
I know that the courses can't feasibly be programmed to accept every single possible answer for every single question, but I do find the Japanese course to be particularly limited and inflexible, and it would be great to see some improvements in this area.