NC Law: Teens who take nude selfie photos face adult sex charges

Someone at Reddit explained that these ridiculous cases come from inconsistencies between federal and state law. In most USA states, adulthood is granted at 16-17 years, but federal law states adulthood is granted at 18 years.

How the prosecutor gets to convince the court that someone is both a minor and an adult illegally taking advantage of himself without being laughed at is beyond my understanding.