The last event might have been post Library arrival, but only by a day depending on how fast the white ravens fly.
Nope, not even close.
Oldtown and the Citadel are thousands of miles away from Westeros. If we take Martin's word that the Wall is about a 100 leagues long, and a league is 3 miles, then looking at the map, a rough measurement is about 2500 miles. The Wall itself is about 600 miles north from Westeros.
Based on online sources and speculation, a raven should be able to cover about 300-500 miles a day, so it would take about 5-8 days for a white one to get to Jon from Oldtown.
Based on online sources and speculation, a raven should be able to cover about 300-500 miles a day, so it would take about 5-8 days for a white one to get to Jon from Oldtown.
But Martin doesn't like to talk about exact things, like the distances or population sizes, even though he has probably done some math about the world. Stuff like, how many people a given size of land can sustain with medieval agriculture and the abnormal seasons (multiple harvests during long summers but long periods of time having to live from reserves etc), or how many peasants per feudal lord, how many soldiers based on the size of lands and so on. There's a lot of historical data on this and Martin did a LOT of research - particularly about the period of the main inspiration for the books, the War of Roses.
The point is that Westeros is big (and Essos is even bigger), the distances are huge and travel takes a lot of time, especially for armies, and even information moves very slowly. I actually find it pretty nice that even though we're talking about a fantasy story, there's no instant travel or communication - this helps to make the story somewhat more unique, interesting, and dramatic.
Also, considering the long travels of some characters, this also means that the story so far had to take several years, which also helps with the child actors growing up in the TV show making sense. Although, the writers could have made this more apparent, especially as there are no seasons passing the way they do in our world. Still, we've seen Dany getting married, pregnant, and giving birth (...) all in just the first season, so there are some hints at least.