Spoilers for Morfonica band story

So I don’t know if anyone’s talked about this, but Rui told Mashiro that she gave up on the violin because she felt like she wasn’t talented enough to have a future playing it. She said she couldn’t be like “that girl” who was very good at the piano.

I’m thinking... maybe that girl is Rinko? It would make sense, considering Rui and Rinko both played in competitions, and we know from past event stories that Rinko is considered very talented.