Responses
im pretty sure in this chapter they went ahead in time bc last chapter they were at a concert and said something about how they wish to perform like this someday. Next chapter they are talking about having a performance. Most of the story they are in their last year in middle school but the time does jump around sometimes.
also this link explains the timeline a bit, hope this helps :)) https://zhanxixis.tumblr.com/19daystimeline

Wait- THEY ARE MIDDLE SCHOOLERS???