When you are young, life seems endless and countless. If this is you, I recommend you look at the charts provided by the folks Wait But Why. They break down your life into weeks and show you how it maps out over time. For example, like this:
They even have blank charts you can use to map out your own life.
It’s sobering to consider. You have less time than you think. If you believe that and use that to motivate yourself to appreciate life, then great. If you don’t believe that, head over to that site and do the math.