I was listening to the radio at 12 when they came out with their first albums. I was listening, but had no idea what the songs were about.
Actually, at 15 I had a friend who was very into Steely Dan, and he kept playing their stuff for me and I just wasn't ready for it yet. I tried to like them, then decided I hated them (easy to do when I got into the whole punk thing at about 19) then finally came round to liking them for real in my mid-20's. So I have a long, checkered history with Steely Dan, but I like 'em. Really. (Well, there are a few tunes on Aja that I still can't abide, but apart from that...)