Well, nobody says that those who “get married” or “do well in their work” are (1) happy and (2) feel like they have “grown up“. If you think that you haven’t grown up based on whatever that standard of growing up is - but feel comfortable and happy in your own skin - then so be it. Who cares. Embrace yourself, flaunt your personality, be confident and do what floats your boat! If you are unhappy with yourself, then very likely, it has nothing to do with feeling grown up. You would be unhappy, dissatisfied and uncontented regardless. So list down what you wish to achieve in life, work on an executable plan, stay disciplined and take down your problems one at a time. You are at a great place with all the time in the world to experiment and discover yourself as long as you stop worrying and mirroring the life of others as success factors. Lastly, to address your concern that others seem to be doing better than you at your age, remember this: it’s not how you start the race, its how you finish strong!