Steven Universe - War Timeline (as of season three)

Nice graph, but it relies on the conjecture that the war began 5500 years ago. Except they were already fighting as early as 5750 years ago. So what Pearl most likely means isn't that they began fighting 5500 y.a., she just means they were already fighting by that point in time.

If the CGs began their fight, let's say, 5800 y.a., "the thousand years of fighting" would have ended about 4800 y.a.. In that case, Bismuth's bubbling (5300 y.a.) would have happened in the middle of the war, which was around the time when the Beta Kindergarten went online. Therefore, Jasper's creation and thus the shattering of Pink Diamond must have happened after that. That would paint Rose in a rather negative light.

But if it all began even earlier, let's say, 6000 y.a., Beta Kindergarten would have already been operational for a few hundred years by the time Bismuth was out of the game. Pink Diamond's death might have as well occurred by then, meaning that in her confrontation with Bismuth, Rose just didn't want to repeat past mistakes.

Personally, I think Bismuth did get to fight in the latter half of the war a bit, because when she and Garnet alone took down three entire battalions of Quartzes, those must have been the shitty Quartzes produced in a rush in Beta Kindergarten. Still, this doesn't clarify whether Rose killed PD before or after bubbling Bismuth.

We should just wait and see, I'm pretty sure some clarification, maybe even in flashback form, is coming.

No, it must have happened after Jasper was created, because Jasper belonged to Pink Diamond's court and was really passionate about it. So Pink Diamond must have still been around when Jasper hatched, otherwise Jasper would have belonged to another Diamond in the first place. And since Jasper originates from Beta Kindergarten, which was set up halfway through the war, Pink Diamond would have still been active at that point.

So Pink Diamond could only have been shattered in the second half of the war.