Hmm... I wonder just how much the 'youthful' look is caused by avoiding the sun or by Autism. This begs a study!
Well.. .I for one don't suffer from what a lot of (presumably older) people have... crow's feet. Reason; I wear shades throughout the day and put any lightsources in the house to the minimum that's pleasant for me so I don't have to squint my eyes.
One can also wonder how much "pasty white" is connected to looking young, lol. I avoid the sun and have been for most of my life (got a sunburn once in my life, if that's an indication how little sun I actually see). Even in summers I go out with long sleeves most of the time and clearly having a lot of hair on my head and face blocks out a lot of areas, for sun to do it's work.