The Mage Queen by Alanna Honigman

The Queen of the Kingdom of Naetrynia was revealed to be a power-hungry witch that used her powers to manipulate her people into worshiping her as though she were a goddess. When the truth was revealed, however, she cast a curse of eternal winter upon the land before making her escape. She now resides within a spire just beyond the forest that surrounds the city, biding her time until she may have the strength to conquer and reclaim her throne once again.

Or so They say.

When one is raised hearing nothing but horrible things about a certain person, isn’t it natural to believe them? Your family, your friends, the whole world around you agrees unanimously upon a single fact—so it must be true.

And if you disagree...well, perhaps you’re evil, too.