We all very well know that, Earth has been made 4.5 billion years ago. Suppose, we are to explain the age of the star and we say that it is 27 billion years old. One year is the duration of time taken by the earth to revolve around the sun once. Before the origin of Earth, how could we explain the time duration because we don't have any point of reference for the time. Suppose a star took 'x' duration of time for its formation. How could we explain it on the basis of years because, the concept of years had come long after the formation of the star. So, I think, the time expressed in years (more than 4.5 billion years ago) is wrong.