Taylor Swift writes her own songs. That much, we knew. But when she decides to take on a rare cover song, she can make it her own before she even gets to the chorus. She’s done that with this live cover of Tom Petty’s “American Girl.” You can get it as a download, a ringtone or even a ringback if you like it so much you want to share it with the world. The song is literally about a decade older than Swift, having been released back in the late ’70s. But it’s one of those classics everybody knows. Even Def Leppard covered it. So this song is inevitably what happens when young country artists spend any quality time with old rock stars.