Hey Anon, I'm not sure if Yamada's line "最後の勇姿になるかも"/"That might be my last hurrah" is properly translated. Their conversation from this panel and the following page feels like a setup for something regarding Kana's band and her school, so I'm not sure why Yamada would be talking about herself.
To me, it feels more like "That might be your (Kana's) last hurrah".
Perhaps she's talking about "つづく"/"Moving Forward", which is essentially her love song like they talked about last chapter. But I guess there's too little info so far to be certain.