Just when I get the old Marquez/McCarthy feeling that I needn’t ever write another word Calvino jumps up and verifies my thoughts:
But how to establish the exact moment in which a story begins? Everything has already begun before, the first line of the first page of every novel refers to something that has already happened outside the book. (p. 153)
Even in the present tense, a word read is in the past. "I see" becomes "I saw" simultaneously with the reading–no, with the writing. All written then, puts a different meaning to the term "flash fiction." Calvino goes on:
Or else the real story is the one that begins ten or a hundred pages further on, and everything that precedes it is only prologue.
So here he is referring to the narrative structure and noting that, even linear, it’s beginning point may be unknown because it has indeed occurred, but is not necessarily written down; nor can it ever be.
The lives of individuals of the human race form a constant plot, in which every attempt to isolate one piece of living that has a meaning separate from the rest–for example, the meeting of two people, which will become decisive for both–must bear in mind that each of the two brings with himself a texture of events, environments, other people, and that from the meeting, in turn, other stories will be derived which will break off from their common story.
While Calvino is focusing on the characters of a story (a main plot being the meeting and changing of the two), he may also be including the past of the reader, since I, we, whoever, is reading this particular book is so involved as to be a character himself.
Calvino, in this last paragraph above, also appears to expand on the notion of "after" as strongly as "before." Prime hypertext manner of thinking. The story need not end, it need not start here or here or there, and endings are continually changing.
The Lost Children: A Charity Anthology
Argh! Exactly what I’m struggling with now with my novel in progress. The story begins based on a particular event, but then there are infinite choices for how much of the before and after for each character to bring into play and help move toward an end. It’s a complication I had not previously anticipated!
That really throws a monkey wrench into the flow of creativity, doesn’t it?
Do what’s best for you, but I’d likely write it ALL in, then take out or move around what you deem unnecessary in the rewrite. Lot’s more work, but then you know you’ve covered the bases.