Time is an extremely complex subject and a simple answer can't really suffice here. You could say that there is only an "eternal now", past and future are just constructs we create to explain the chronology of events. But it is my understanding that time IS relative. Since we live in a physical world, it will always take time to do something [move from one point to another, even if that is non-physical, like a goal]. The way time is relative is the speed at which you get from point A to B. The perception of time can drastically change in meditation as well.
But you won't find 2 people side by side aging differently or something like that.