There are no invisible lines

I remember clearly how, around 15 or 16, I had this belief: once you hit 40, you&apos;re definitely an adult. I looked at those who, in my eyes, were older, stronger, confident people, and I thought — to become that starting from this ... you must definitely cross some invisible line at some point, and then you just &apos;know.&apos; Well, I&apos;m (almost) 40 now. I&apos;ve learned that — sadly —…