The First Tide: A Mystical Society series. Grimwood Academy, #1

In an academy where suspicion rises, she sets out to make a difference. Can mermaids dream?Grimwood, the first academy for species built after the war, has opened its doors to the challenge, and Sheylla is up to the task. As an ocean mermaid, Sheylla Nymphaea has spent a restricted life among the folk of Streamstar. But when a letter arrives inviting her into an academy of diverse species, she grabs the opportunity by the tail.
Sheylla wants to change the world, but she's in for a surprise. When her powers misbehave, she learns she's a host of the ocean spirit, destined to battle the upcoming threat. With unknown danger lurking, and Grimwood's magic crumbling bit by bit, Sheylla and her unusual circle of friends must race against time to discover the truth. But when another ocean child arrives, those unacceptable friendships are put to the test.
Can Sheylla defeat the enemy without losing herself?The First Tide is the first installment of the Grimwood series, a coming-of-age tale. Teens discover their powers, a powerful enemy threatens the existence of the world, and a heroine must choose between duty and her heart.