Just to elaborate on this idea. I think there could be a moodlet for them called "What's happening to my body" as they go through puberty. I also think there could be something where a sim parent tries to hug their younger teen and they pull away because it's uncool and parents are lame. They could also have good relationships with siblings or parents and when they hit their younger teen years. They don't want anything to do with them. There could be different phases that younger teens go through based on their personality traits like a boy crazy or girl crazy and parents want to stop them because they don't want their baby to grow up yet. Or maybe they can be obsessed with different things like bugs or a certain skill. Maybe have them want to be something reIated to that skill. Like a rockstar because they listen to rock music a lot. also think that this life state could be where teens figure out who they are and want to experiment. Maybe they want to be an adult as fast as they can or they are scared to grow up and want to stay a child. Maybe there could be a few special traits or phase for younger teen sims where they regress and act like a child or toddler and parents can react to it either positive or negative. Parents could reprimand them for growing up to fast and reprimand them when they are acting like a child which gives them a not knowing what they want moodlet.