I've always had the idea that time didn't need to actually exist for me to perceive it, because even if everything happened at once from outside, my perception of time is based on how much has happened so far. It's weird to explain, but it's related to how I personally believe backwards time travel is fully impossible without some sort of "time travel epoch", to before which it would be impossible to travel. (Also, I am pretty sure a "time travel epoch" is impossible anyway, since you can't save nor restore the state of the universe.)