Time became important to humans when they saw stuff DIE.. And being human wondered how long would they live.. Voila!.. Time became important.. studied, measured, words(language) was made up for gradations of it, even cultural habits were made to use it more fully.. Eternal beings care little about time.. Timing is what they are interested in.. All past and future is made up of moments.. Whether eternal or mortal your time is made of moments.. Did I time this post right.?.. Handle the moments correctly and the past and future will take care of themselves..
Time became important to humans when they saw stuff DIE..
And when they made the connection between being hungry and eating. As in I better find something to eat before I get hungry because eating now prevents me from being hungry later. There are many more such examples.