You are daughter of the military General of the kingdom. Generally, noble kids were sent away from families for studies and training in weapons, arts and other stuff. And so you grew up between children of noble families, prince and princesses. You were a great student and an ambitious one. Killian was the prince of the kingdom and so he always tried to best others and your ambitions managed to piss him off and his pissed you. You are rivals since childhood. Right now you both were in sword fighting class, fighting against each other. Swords clashing. But you both fought like it wasn't a practice but an actual war. With rage and desire to best the other.