"Because time flows, change is possible."

This puts the cart before the horse.

Because existence changes, time is perceived.

If nothing changed, the universe would be completely static. Change is necessary for existence. A changeless universe would be remarkably dull as we would have no need to perceive it. Awareness is only necessary to react to a changing world.

Time is a mental phenomenon created by the memory of our changing existence. If we didn't have memory, we wouldn't perceive time; we would only perceive change. Time is an illusion created by memory. Time only exists because in our minds we can recreate a previous "now" by recollecting the binding sense experiences we experienced. Past is only created by memory, and future is only created by fantasy. All we have is now.