Looking for some help seeing whether I have understood the usage of だけに in the below. To summarise the conversation 御園 is saying that she was jealous of 佳奈. As she was explaining why she was jealous she became embarrassed and tried to change what she was going to say part way through, leading to the eventual ツッコミ by the narrator as the three of them spent most of the day eating out yesterday.
御園 says 音楽科だけに. Is this just to emphasise why she is jealous?(she specialises in music). edit: Thinking about it I'm not sure that makes sense. I originally thought she was saying that 佳奈 went to 河井楽器 but now I'm thinking she might be saying that she went there.