If your story isn’t strictly chronological, you need two timelines:
The timeline of everything that happens,
and the timeline of the order in which the story is told.
This can be more widely applicable that you think. Even if you don’t narratively jump around in time as much as I do, you might have backstory revelations that warrant a second timeline to highlight what the reader learns when.
Some people love ‘em, some people hate ‘em. BUT, even if you would never outline at the outset, have you considered outlining after the fact? That’s when they’ve been most useful for me. Then I see what I actually have.