Females that are about to drop will get even bigger and "squared off" . She looks like it could be awhile still. You dont need to seperate her, just leave her in the tank. You should seperate the fry at about 1 week and start feeding them as much as they can eat. Putting female guppies in a trap stress them out and alot of times they will die or abort the drop. good luck. It is pretty easy and straightfoward.