Lol. I hate to admit it but I always used to do well on multiple choice questions tests because I tend to just rely on my instincts and don't bother trying to second guess my choices. It meant I was always relaxed when it came to that sort of thing. So a combo of luck and some studying that would leave the info SOMEWHERE in my brain even I can't couldn't just pull those facts out consciously on command.
Sadly, Maggie's luck will be mainly played for laughs. But yeah, this is her second magical ability. She is basically the Goddess of Luck, to the point that if you tried aiming a gun at her and pulling the trigger the gun would misfire. It's that OP.