If you could choose one age to be for the rest of your life, what would it be? You would still have the same personality, mental abilities, and memories. If you picked being in the body of a child, you wouldn't have the social and legal restrictions of a child, but you'd have the physical restrictions. For the older ages, you wouldn't have the wear and tear of a normal elder, but you'd still have less muscle and fat. Anyone be like Gandalf and be old forever but still kick butt?