Steve Winwood was about that same age when he was with Spencer Davis.
Back in the early 60's, there was a large music shop in Birmingham, England called Yardleys. Charlie, the owner, ran the main store. My dad ran the guitar shop, which was a ratty little hole around the corner.
Yardleys was a common drop-in for musicians working in or passing through the midlands, and one of my dad's favourite visitors was Muff Winwood.
Dad was covering for the boss up at the main store one day, when Muff's little brother Stevie dropped in. Stevie was probably about 15 at the time.
There was an electric organ and a Leslie in the keyboard area, and he asked my dad if they could plug it in. While my dad was helping him set it up, Stevie explained that he'd always been curious about keyboards, and fancied trying one out.
Once they had it plugged in, Winwood began to tentatively pick out a few notes, obviously fumbling to figure out the pitch relationships between the white and black keys. After about 10 minutes, he began to falteringly pick out a few melodic phrases. Over the next while he gradually improved, until he was rocking out as though he'd been playing keys for years.
My dad was absolutely flabbergasted at how quickly this scrawny kid picked it up, and spent the next couple of weeks telling anybody who would listen about Muff's amazing little brother.
You can imagine my dad's embarrassment the next time Muff was in the store, and explained that his brother was something of a con artist. Apparently Stevie had been taking piano lessons for years at that point, and the whole thing was a charade that he liked to pull on unsuspecting salesmen...
After he got over the fact that he'd been so thoroughly conned by a teenager, my dad found the whole thing terrifically funny, and it became one of our favourite showbiz stories.