So...in factions, when does the whole Luxon/Kurizick thing begin?

I'm currently in Nahpui corner, and I am just curious when you start getting involved with the Luxons and Kurzicks, like when you do the befriending quests.

as soon as you leave the big city place

And when is that? xD

As soon as you start the befriending the Kurzick or Luxon mission. I think you can earn some faction previous to this with the 2 storyline mission, as well as the charting quests.