So, Abbi is obviously the girl on the cover. Black wings and all. Just with a tail and sharp claws that hide under her human nails. Her tail is barbed with a stinger that injects venom into any enemies blood stream.

Now to her wings; a diagram of how big the wings is shown

They first started at the 2 year mark. Now, they are at the 4. In the end, the wings will be at 12. Abbi is currently in her teens, so you can decide how old she is. In my opinion, she'd be like, 15-17.

Abbi's wings are black, like on the cover. That was what they looked like when they first started growing. Soon, she might be able to fly away from Charles and meet some new friends.