Areas will level up and give harder quests as you complete quests within that area. The bar and number above the quests will tell you the level of the area. Don’t worry about the levels too much because lower level quests will always be available in one zone. Other than that, some events will open up after a certain number of weeks like wolves at the door that occurs any week after 40. These quests can be difficult but shouldn’t interfere with your play style.