I can't argue astronomy. I'm not an astronomer. But I do know words and words mean things. This college professor, who has been teaching for a number of years, quote about theories is accurate. Theories can, and do, change. However, there are many scientists today who would like you to believe that theories are laws. They are not.
I take it you are not an astronomer yourself so your astronomical opinions are about like mine-next to meaningless. (Since you've labeled yourself "Physicist" you actually may have more knowledge about astronomy than my two semesters in it. But I digress.) I would suggest what you find wrong with this author is his statement that theories can change-not his views on astronomy. Astronomers better than anyone knows how frequently theories changes and, at least, are up front about that.
Well, I have a college degree in it...does that count?
But in any case, you don't have to be an astronomer to know that "the age of the universe" falls into the category of "fact" and not "theory". And you don't have to be a scientist to know that facts, as far as they pertain to science, can be wrong.
As for whether theories change, often they do, but that doesn't in any way address the point that you were attempting to refute.
However, there are many scientists today who would like you to believe that theories are laws. They are not.
Codswallop. Scientists know the difference, even if you don't. The fact that theories can change and laws can't makes theories stronger than laws, and far more important to science. Theories are conceptual models; laws are empirical rules of thumb. If a theory is wrong, it is either discarded or modified; if a law is wrong (e.g. Ampere's Law), it remains wrong.
I would suggest what you find wrong with this author is his statement that theories can change-not his views on astronomy.
Your theory is wrong. Change it.