It sounds to me like the song is written from the perspective of a guy who's thinking about a girl he used to be with. And in particular, he's remembering two instances with her that he refers to as "flashbacks" (i.e., picking her up from her house, and seeing her dance on the high dive)
I think the "someone else's song" line seems to become significant in the end when its revealed that now someone else is picking her up from her house
It sounds to me like the song is written from the perspective of a guy who's thinking about a girl he used to be with. And in particular, he's remembering two instances with her that he refers to as "flashbacks" (i.e., picking her up from her house, and seeing her dance on the high dive)
I think the "someone else's song" line seems to become significant in the end when its revealed that now someone else is picking her up from her house