The things you mention here^ all require the same type of skills, which is why they are comparable (although I could still argue that a person could be on a wheelchair and could travel around the world on a plane but couldn't walk 10 feet, a person could be allergic to an ingredient in the cupcake and could handle beer but not the cupcake, etc, but that's being pedantic). Having sex as a young kid with a much older person, and joining the army, require different types of emotional maturity and experience. Which is why they aren't comparable imo. As I said, sex is a private, intimate experience that can make you completely vulnerable to another person. Joining the army (even handling risky information and guiding men into battle etc) doesn't require the same kind of emotional tools.