Your opinion of "fact" differs from many in that it has some flexibility. I think your definition of "fact" is extremely useful, and I agree with it not completely, but greatly. You and anyone else are entitled to have your own definition of "fact" but I think that you will need to understand that when most people use the word "fact" they mean not something that is defined by originating from a source, but something that is defined by its essential truthfulness, by which I mean, possessing a truthfulness that cannot be contravened under any circumstances, whether through source or the passing of time or anything else of similar nature. For most people who typically discuss "fact", a "fact" is stable, enduring, and immutable, not susceptible to "change" or being "proven wrong".