They open in childhood -- with a sequence of events too large to be shuttled into a prologue -- and wind on to adulthood. . .
Without, of course, a constant flow of excitement and adventure on the way that you can turn into a story. For one thing, it would have to be a series to cover all the years. For another, it would have to be an episodic series, with no story structure to contain all the books, because that would be too large to be taken in, and so not really a story.
Thinking of breaking the work down into Parts, each of which can cover a different period. And do a lot more filling in of the gaps by accounts and summary. . .
And it's a problem for many stories. From a fairy tale novel which opens with a Hansel and Gretel tale but then transitions to tales where they are adults and to marry, to a sword and sorcery where a child sees his family massacred and vows revenge -- but first must prepare.