Help me find this book

This was a book I read about 7 years ago and it was a young adult novel.

The main character was a young man who's parents were royalty and sent him back in time to protect him. His guardians who acted as his parents could read his mind and he doesn't know it.. One day his family gets attacked and he takes a boat and runs away and ends up in New York. Somehow he meets an Asian looking girl from his home time who trains him in the powers of his family. She teaches him how to fly and she is able to shapeshift. She nearly sleeps with him until he hesitated in saying yes until she shape shifted into her "sexy" form.