Do anybody know that if im in the middle of a savegame and I add a event or desion or new country to form will i get thouhgs events and destion sin the game still?
Yes, yes it should work. I have done this before. My change was adding an event to form the Roman Empire as Byzantium, after a good 200 years into the campaign. It worked just fine for me, so unless you build your event based on other events or a date that has already passed, you should not have a problem.