When should I start to worry?

I find myself whistling along - even boogying - to a Blondie track. Why is that? Well, let me tell you, as I'm the one asking the questions anyway. I got a freebie CD of covers by a jazz trio called The Bad Plus. I won it on Altered Radio, the Oxford student radio station. I bet I was the only one entering the damn competition, but never mind that. There's an interesting cover of Nirvana's "Smells Like Teen Spirit". I also come to like the funky melody at the end of "Heart of Glass". Later, I find out it's a Blondie track, so I track it down (no funny punny intended, well, I suppose maybe an ickle wickle punny wunny). The boogie rhythm is still there, although not as cool as the way The Bad Plus do it. Should I pay my life's membership fee to the Club of Dad Music already, at the tender-eared age of 21? I'm already a fan of James Taylor, and had tears in my eyes at his Earl's Court gig on 22 July. At least I didn't sing along swaying with my eyes closed.