Is this A Curse So Dark and Lonely (2019) by Brigid Kemmerer...? It's the first book in the Cursebreakers trilogy.
Fall in love, break the curse.
Cursed by a powerful enchantress to repeat the autumn of his eighteenth year, Prince Rhen, the heir of Emberfall, thought he could be saved easily if a girl fell for him. But that was before he turned into a vicious beast hell-bent on destruction. Before he destroyed his castle, his family, and every last shred of hope.
Nothing has ever been easy for Harper. With her father long gone, her mother dying, and her brother constantly underestimating her because of her cerebral palsy, Harper learned to be tough enough to survive. When she tries to save a stranger on the streets of Washington, DC, she's pulled into a magical world.
Break the curse, save the kingdom.
Harper doesn't know where she is or what to believe. A prince? A curse? A monster? As she spends time with Rhen in this enchanted land, she begins to understand what's at stake. And as Rhen realizes Harper is not just another girl to charm, his hope comes flooding back. But powerful forces are standing against Emberfall . . . and it will take more than a broken curse to save Harper, Rhen, and his people from utter ruin.
From a user review:
Harper comes from modern day DC. She has cerebral palsy and she’s bad ass! Harper gets sucked into another world when she attacks Commander Grey when she sees him carrying a woman away. She thinks he is going to kill the lady. Suddenly Harper gets transported into another world through Grey.
