Ah, Time, a fun one...
Time is a means of organizing empirical knowledge of the Universe. It's easier to say, "Time's moving forward" than "all things are moving simultaneously in their set directions and velocities". Time is relative, set to a specific observable movement or change. The vibration of Quartz, the (relative) movement of the Sun, the phases of the Moon, etc. are all used as standards by which we measure other movement.
We say "The car is traveling 30 miles per hour," but what we mean is, "Compared to 1/24th the movement of the sun's cycle, we will be 30 miles from our current position, along a set course." Time is relative, just as movement and distance is relative. It is not special in that regard.
If by "Illusion", you mean "only in the mind", then I can wholly agree with you. There is not a thing called Time that exists apart from the mind, since it is unobservable in reality apart from the mind.