is it beneficial to start studying for ap world before even taking the class?
Not really. If there are no summer assignments, and you have spare time, you can read the first coupleof chapter of the text if you have it.
It never hurts to go over stuff over the summer for any class, in the abscence of other things to do.
Do note that for AP English classes and all the AP science classes, there often will be summer assignments and/or review of material.
I could find hundreds of better uses for my time.
I bet I could find more 