Genuine confusion here -- how can you assert time is real?

From my limited understanding, time is merely the measurement of change. A comet goes from point A to B, and like a screen flickering, it is in a discrete point in space every step along the way. It is time that is introduced when asking ourselves, "how long did it take?" or "when was it at X?" but how can it be woven into the fabric of the universe? If we take reality to be right here, right now, it doesn't seem to exist but rather is a human invention to help us map change.