It's never too early for AP World students to begin reviewing.
Amanda DoAmaral, whose You Tube channel has some terrrific reivews for key concepts in World History, just rolled out a 7 day reivew challenge for students. Sign up for the 7 day challenge, and she'll send you a review activity each day.
She says that the activites will revolve around the most important people in AP World History.
Teachers can sign up too and she will send the activities to you as well so you can review them with the students.