XVI. I have a song

I was a boy, and still I am, according to my mother
I was crazy, and still I am, so say my sister and brothers
I had a song, and still it I sing, though it is louder
I have a song, and still it I sing, though it does grow shorter
I have a calling, it lures me on, according to my spirit
I have a future, and I am content, for I know that I am in it