No No NO do not trim your fan leaves!!! when you flower you cut down the nitrogen; or most of it...your plant then takes all the available nitrogen from the leaves causing them to yellow wilt die and fall off...let them...fan leaves are the plants temp controls
and they provide mecessary sugars for thc production during the dry/curing process
cutting them all off will leave your plants without one of their senses, so to speak ...good luck, hope this helps.