As a kid, the only time you're told to be quiet is when you're in the presence of others, being rude, yammering on, but your curiosity and opinions are cute or a good sign of intellectual adventuring.
Growing up isn't any harder than being young, but there are facets of every stage of life that are challenging.
Perhaps the hardest thing about growing up is learning your voice, for the most part, doesn't matter. You can shout into the void, into the web, onto paper, into a co-worker's ear, but for the most part, the words and streams of consciousness will live and die amidst a very small number of people, and most times, it will live and die only amongst yourself. Your voice, your story, may go untold. A tragedy, if such a thing could be called as much, for the over 7 billion people on this planet are unique like a fingerprint, each with their own upbringing and values and knowledge and background.
You may call it cynical but I like to think of it as being realistic. My voice, for instance, confined to anonymous online accounts and family, a history of failed attempts of short stories and a god-forsaken blog with perhaps no regular visitors. I know that I really have nothing valuable to add to the void, nothing painstakingly original and human or touching or challenging, standing on the shoulders of those before and yet still failing to stand taller than them.
But I'll continue to throw my voice into the void, for what other choice is there? At least, then, I can say I tried, and here one day will lie my body, and I will have been hopelessly alone, but a stubborn asshole all the same. Insignificant, another mind lost to time and space, barreling towards the heat death of the universe, all from the nothingness of death.