What can I do in my 20s to feel better about myself

So basically im turning 20 im a few months, for some people it seems exciting but for me I feel like I'm just getting older without doing much. Seeing people around me achieve things in their lives make me feel insecure. It's not that I don't try to achieve something but I don't think I tried enough. Is it too late to do something in my 20s? What are some skills that can be helpful for me? And what are some social activities, courses, etc that I can take part in to boost my social skills and confidence?