I think this song is about a child seeing the world for what it is. The child has so many dreams of what he/she wants to do in life, but also realizes his/her mortality and the fragile state our world is in.
& To continue on the child realizing his/her mortality... He/she knows he/she will return his/her body to nature, part of the dirt, at some point in life; it's inevitable. It's serious and innocent at the same time. Great track.