Why is my mate a demon??

Hello, I'm Rose, I am 17 years old and live in a big house with about 30 other people. Why? Well because they'll part of my pack. That right I'm a werewolf. Not just any werewolf but the daughter of my pacts alpha. Life was going great for Rose, good grades, amazing friends but this all changed when she finally met her mate, a tall dark haired demon but hey, at least he has a 6 pack!!