Slow ballad, almost melancholy-feeling, about moving forward and making changes in your life and yourself.
Other songs like this one:
Times of Your Life - Paul Anka
This is a very slow nostalgic ballad from the 70's, about when "you wake up and time has slipped away". Nostalgic, rather than sentimental.
Everybody's Changing - Keane
For those of you being left behind by someone you treasure. The song is about making meaning of your place in the world while everyone else moves forward in their lives. An atmospheric piano-rock and synthesiser song.