I had the same thought, but this tendency to increase the age of characters is not restricted to multi-season shows or even to fiction. Most people today are unaware that Pocahontas was a preteen at the time she played her primary role in history, or that Mary the mother of Jesus could not have been more than 12 or 13 at the time she gave birth. These roles have both been played by adults for so long that many people downright refuse to believe the truth.