It is difficult to explain this but I'm in my late 30s and I feel like I'm only just learning the social norms that most people seem to know much younger.
For example just not being too intense with conversation, not telling people too much or rambling about my problems, being more laid back about making plans, realising people say things not don't always do it and it's ok (I think) to do that, being nice rather than right. I feel like Sheldon Cooper saying all this and wonder whether there is something about me that has made me take a long time to learn all this.