15. "Fifteen" (2008)
"In your life you'll do things greater than dating the boy on the football team / I didn't know that at 15." Still south of her twenties, she sings her compassionate, sisterly yet hard-ass advice to her fellow teenage girls. (Spoiler: boys are always lying about everything.) Childhood pal Abigail Anderson will always be her coolest BFF of all time; Taylor was a bridesmaid in her wedding just a few months ago.
Best line: "We both cried."