Could it be because of diet and medicine that people have started to look younger? Also, I think, a lot of it has to do with hair and your clothes. I saw pictures of my mom and dad in high school and they looked like adults.
Despite the aggravation of moving around at almost 9 feet tall, he actually seemed like a pretty happy person. In most of those video clips, he's just smiling and going with the flow. He looked so much older than his actual age though. I never would have guessed he was only 22 when he passed away.