Why Obi-Wan Kenobi Aged So Fast
Why did Uncle Owen, Aunt Beru, and Obi-Wan Kenobi age so much in the nineteen years between Revenge of the Sith and A New Hope? Obviously the real answer is that they were played by different actors, I know, but there is an in-universe answer as well. The novel Ahsoka by EK Johnston has an interlude about Obi-Wan which takes place only a year after he settled on Tatooine. He notes how much the desert climate had affected him in such a short amount of time. The fact of the matter is sun damage will cause you to age. So think about living in a desert. And now think about living in a desert with two suns! It would almost certainly accelerate the aging process.