In your twenties, your life seems to span out for years ahead of you.
I am now in my mid-40's and life definately seems too short.
I feel I have ony just got into the swing of it and there doesn't seem to be enough time left now.
Maybe thats the point, you spend your teens, twenties and thirties learning and then you hit mid-life and you suddenly are faced with your own imortality and are forced to make choices.
Both my parents died over a year ago due to ill health. They were both only 63, so I am aware not everyone is lucky to make it into their 80's.
So I would say make the most of everyday as you don't know how long you have got.