Think life is short? No. Life is the longest thing one will ever experience. But since time is a relative term, you have the rights to decide how you pass time and how time passes you.
We allow time to guide us what to do because our perception on time is bound by our own limitation. What time of the day do we take our dinner; which month in the year do we go for holiday; at what age do we get married; at what age do we retire and play frisbee with our grandchildren, etc. None of these will matter if there is no time, or limitation to our time.
We think rocks are permanent - but in fact they are not. They are constantly eroding. It's only when we place them on the scale of human lives, they symbolise eternity as they will outlast us. That is why we build our most important monuments with rocks.
I guess this is where meaning of life comes from - we are limited by time and we want to do something to outlast our limitation.
I turned 25 yesterday. If I would live an average person's lifespan, I will have another two cycles of 25 years to hang around.
In the first 25 years, like everybody else, I was busy growing up, understanding the world, and anticipating what the world will become.
For the next two cycles of 25 years, I will continue the process but with one additional mission - create meanings that will outlast me.