The science is well evidenced, from multiple, consilient sources. Scientists may disagree on details, but the age of the Earth is pretty well established.Scientist really don’t know for sure and all theory as with the views of science concerning the age of the earth and creation, which is why the science is ever changing. I have a different view from the Creator.
Science is ever changing because it's ever learning; ever discovering new facts. It reflects the best conclusions, given the latest facts, and it's always open to new evidence, challenges and interpretations.