Chances are, you’re already following a slew of young adults with envy-inducing lives on social media—authors, actors, athletes, YouTubers, the works. And it may seem like they sprang fully formed and awesome from some factory that churns out success stories as fast as you can say “I want that life!” But the truth is, at some point, they all struggled with the same challenges you’re facing right now, from friend drama to procrastination problems. So we asked a few of them: What do you wish you had known as a teen? Here, just in time for the new school year, are some surprising lessons from three people who are now #killingit in their chosen fields—plus simple tips to apply their wisdom to your own life!