There's video of Led Zepplin guitarist Jimmy Page performing on some British talent show in 1957, when he was just 13 years old.

Jimmy and his skiffle group played "Mama Don't Want To Skiffle Anymore" and "Cotton Fields".  It's been around for a while now, but if you haven't come across it yet, it's pretty awesome.

When the host asks Jimmy what he wants to do after he graduates, he says, quote, "I want to do biological research [to find a cure for] cancer, if it isn't discovered by then."

Here's video. Jimmy is the guitarist in the dark-colored shirt. He's interviewed about two minutes in. It's a somewhat awkward conversation. The second song is after the interview.