What am I?

Lacey Morrison, has never been in the ocean before because of her "over protective" mother. She never understood why, until the day, or should I say night, she did. She has no idea why she is what she is, but she learns to accept it, except when her friends and her boyfriend find out. And what happens when she meets a guy like her and she starts to like him, but he seems to hate her, so will she get the guy or will she just have her mother to keep her company.