Time is in the eye of the Beholder

Time, like beauty, is in the eye of the beholder.

Dog years are converted into humans years, (7 dog years for every human year?)

Is time the 4th dimension or at least a dimension? Yes, just like the 2nd or 3rd dimension (2-D or 3-D) our perception of time exists(its just not visible)*. But I think it varies between everyone. You can't claim that two people that are the exact same age are at the same point in their life, because time, just like beauty is in the eye of the beholder.

*Who's to say that if you can't see it, its not there. Math doesn't really exist, you can't find the number 1 in nature, its a concept that humans have created. A lot like time.