There are things that happened to you when you were a teenager, things you had no control over at the time, things that changed the course of your life. For example, that time when the headmaster told you your choice of A-Levels didn't fit with his timetable, so you had to choose different subjects. You made the most of it of course, changed your expectations, reassessed your career options, and achieved success nonetheless.
Years later you find the time to do that thing you wanted to do aged sixteen and you discover David Lodge's book, The Art of Fiction