Ok what's your point? Legally the adult age is 18 in most states. If you want to argue changing what legal age is that's fine but it doesn't really have anything to do with the main point of my comment. Additionally, this study specifically shows it harms adolescents.

If you're going to apply laws that strip rights away from people you have to have a cutoff somewhere. Unless you're suggesting a blanket ban on social media for everyone.....