Music and Age

I was listening to the song "Before Too Long" by my current musical favorite, Paul Kelly, on my ipod today. I stopped listening and walked to the cafeteria. While I was walking I was singing the song in my mind. The only thing is, here is how I was singing it:

Before too long,
na na nana na
na na nana na
na na na

Before too long,
nana na na, nana na
nana na na nana na
na na

I've heard this song dozens of times, but I have no clues as to what the lyrics are.

A year or so ago, I bought the album Twin Cinema by the New Pornographers. I liked it and listened to it often. Two months ago my daughter decided she liked it and started listening to it. Shortly after that, one of the songs played while we were both present. She sang along and knew all of the words. I had no idea what the words were.
Huh? I've heard the song dozens times more than she has. How is it possible that she knows the lyrics better than me?
You know what? When I listen to songs now, I don't hear the lyrics. I hear the melody, I hear the rhythm. I can tell you the older songs that sound like this and which older artists that this reminds me of. But other than the main lines of the chorus, I hear no words.
Its cool seeing my daughter enter that age where she really HEARS and becomes absorbed in music. Its also neat that she will occasionally like a song that I play for her and she will let me know that she likes it. Latest: She and her camp roommate played Quiet Riot's "Come On Feel the Noise", that I recommended to her, often while at camp. It was extremely nice of her to tell me that.

I guess I sometimes miss my old powers of concentration and that hunger to absorb new things that young folks have.