A lifetime seems like a long time, it's only right at the end looking back where you say "It's all happened so fast". Humans live an astonishingly short time. It is just moments between being children, and having children of their own. Just moments between growing stable and getting minds of their own, and growing old and dying.
Humans live so short, the only way you can pack in what you need in such a short time is learning in every moment. Facing things that are new, that you don't know how to do, that are scary and overwhelming. That means a lot of your life you're going to be scared and overwhelmed, because there are constantly things that are out of your reach. You're always going to be faced with things too big for you. You may want to run away, be afraid, lash out ... All of you will feel these things.
By being strong enough, and gentle enough, we give people a safe place to learn, a safe environment to try things that are beyond their level. And they mange, and become something more, until they hit the next thing. This will be true every moment of your life. There will always be something out of your reach. Sometimes, there will be an older one there to be strong and kind for you and make it easier. You must learn, for others, to be strong and to be kind, so they feel safe in their learning. And you must learn for yourself, to be strong and be kind, because there will not always be an older one to be that for you.