There is nothing half so comforting when nightmares have roused one from pleasant slumber, than escaping to a fantasy world of one's choosing. Charlie Adams was a firm believer in the medicinal value of literary escapism. It was how she found herself sitting in the stairwell between the 12th and 13th floors of the Morning Bell Hotel just outside of St. Augustine, Florida.
This first sentence doesn't read like YA at all. Honestly, I would nix it and start with the second. That's a great line imho. If you can reword the first sentence and combine it with the third sentence, I think you'll have a much stronger opening.