im 17.5, playing for 3.5 years.
i cant say im the god of the guitar, but im doing quite ok..
anyway i dont think you can realy find a teenager who is a realy good guitar player... well maybe in rock and metall you can but not in blues and jazz..
it takes years to learn how to play those styles + it requires certain maturity to play jazz or blues.
another problem with people who dont play many years is that most of them know nothing about sound..