How long was it between when Iroh convinced Zuko to take up the Fire Throne, and Sozin's comet? A day? Less??

AU where Iroh convinces Zuko to be the next Fire Lord MUCH earlier in the series. Zuko, who hasn't been in formal education since was 13yo, understandably panics. He barely remembers his lessons on How To Be the Fire Lord, and they were all focused on how to rule during wartime. Not peace. What does an international peace treaty even LOOK like and how does one go about making it???? How does trade work when you're NOT trying to eradicate every other nation????

Book 3 Zuko spends all of his time teaching Aang firebending, interrogating the other members about their culture's traditions and politics, going on Blue Spirit journeys to raid any passing libraries, and reading everything he can get his hands on. He barely eats. He doesn't sleep. He's info dumping about the DRIEST political texts. The gaang are THIS close to holding an intervention or having Toph sit on him until he sleeps.