Mists of Pandaria will be launching either today or within the next few days for everyone! Here are the official launch times provided by Blizzard.
North and Latin American realms - 12:00 a.m. PDT, September 25
European realms - 12:00 a.m. CEST, September 25
Korean/Taiwan realms - 12:00 a.m. KST, September 27
With this expansion, we’re using a new bit of tech that will unlock the expansion content, make the intro quest magically pop up in your quest log, and allow you to begin playing the expansion immediately without the need to log out and back in. If everything goes as planned this will be a smooth transition to the adventures that await you in the new continent.
See you in-game!
For those curious about how long leveling from 85-90 will take, I have a few sources saying that it usually averages around 14 hours played time.