I just finished reading a book with the actual documents, interviews and investigations on Fatima.
Even in the book it states that the reader will end up with some concerns.
According to Lucia, the Blessed Mother told her that their friend, Amelia, would be in Purgatory until the end of time. if that’s the fate of a child, what hope is there for the rest of us?
Only the Magisterium is qualified to approve a given private revelation, or part of a revelation, as worthy of belief. Even if something was stated and recorded right there at the first investigations, that does not mean it is credible to be expressed by Mary. Even if something is related by Lucia much later, in the 4th edition of some journal, that does not mean it is not credible.
In both cases, if the Magisterium deems it credible, it would be worthy of belief. If the Magisterium did not review or approve it, it is not.
(It is my understanding that much of the later disclosed revelations, perhaps after 1930, are probably not part of the approved private revelation. But if the Magisterium approves it, it would be.)
Since all these Fatima revelations are coming about 19 centuries after Mary lived on Earth, a couple decades one way or the other in the 20th century is not much difference. But the Magisterium review, does matter.