The Selkie Maiden (Book 1 of 2)

Kiera has a deadly dark secret -- she is the descendant of a Merrow -- an Irish mermaid.
Given the enchanted sapphire ring of her ancestor, it is now her time to bear the weight of the sea. Kiera, however, is not all too thrilled with her current life -- as she is neither Irish or American -- having no place to really call home, and no friends to make her happy.
With Merrow's gathering, waiting for midsummer's eve to claim her -- Kiera by chance, befriends a cute grey-white seal pup who protects her from being harmed by another seal. Together, Kiera learns from the seals on how to relax and find beauty in this world.
However, four boys from her class had just murdered her only friend and this was the spark that had awakened her ancestor's powers -- the ocean plunging her and the deceased seal into the icy cold Atlantic Ocean.
Kiera then was saved by a selkie named Nuala who reveals that she is possessed by her own daughter, Una. Her once purposeless life is now thrusted deep into the dark abyss as Kiera finds herself becoming the new Selkie Maiden.