The beginning of the world continues when the world ends. In other words there is no such thing as eternity or infinity, because they are two identical points in a circular coordinational system.
What about us?
We are only tiny particles in the vast universe at certain point in time. A lifetime of a fly seems to us as being too short. But for the fly it’s normal life.
The difference is that we have memory. Short memory of the current life and long memories of another life in when the world was you aka the eternity.
Another problem for us is that we know there is a point in time that everything will end.
Molecules and atoms that constitute our body, also carry memories of the past, and maybe future.
All of this make us regret for all the time that passes in our current short life.