Morgan is my Name by Sophie Keetch

An atmospheric, feminist retelling of the early life of famed villainess Morgan le Fay, set against the colourful chivalric backdrop of Arthurian legend.
 
My name is Morgan... And there aren’t enough words for all that I am.

When King Uther Pendragon murders her father and tricks her mother into marriage, Morgan refuses to be crushed. Trapped amid the machinations of men in a world of isolated castles and gossiping courts, she discovers secret powers. Vengeful and brilliant, it's not long before Morgan becomes a worthy adversary to Merlin, influential sorcerer to the king.

But fighting for her freedom, she risks losing everything – her reputation, her loved ones and her life.