The aftermath of a compulsive reader

I download free books for my kids and myself from Amazon every day. Lately, there have been quite a few vampire books and I know my daughter loves that genre, so I always get them. Yesterday, while going to the car, my daughter(17 yrs old) informs me it's good that it isn't dark yet because she wouldn't be going to the store with me if it was. All the vampire stories have left her a little afraid of the dark. I think maybe she should lay off for a few days.