A Mermaid's Tale

Mermaids have always had the ability to be human AND mermaid. Mermen on the other hand, have never had that power. If you were born as a human but have a mermaid/merman parent, your parents choose they way you would live. As a mermaid/merman or as a human. Ellie Swan was born a human and had a twin brother named Ryan. Ryan Swan was born a merman, along with his mother being a mermaid. Ellie was a human just like her father. When the twins turned 16, Ryan and the twin's mother went to the ocean and never came back. The only thing the mother left her sweet, beautiful, kind daughter was granting her with the most amazing power ever. To be a mermaid. Ryan requested for his sister to have this ability so they may find each other one day. When she transformed, she was given every power in the book, except for one. The power to heal herself. Her mother wanted her to learn to use her other powers to protect herself so she would never need to heal herself. Everything went sort of smooth after her mother and Ryan had left until she found out her father was a merman. Everything turned upside down and she even moved out of her home to a beach house. She lived a normal-ish life until she met this boy...