Beyond the Deep By Trevor Darby

Serina is a young mermaid wishing, praying, dreaming of being something, anything but blond.

In her world, you have to hope your color (hair and tail) changes before your 13th birthday. Hers hasn't. She did well enough on her entrance exam to be admitted to the prestigious Academy, but if her color doesn't come in, she will be kicked out and banished.

It is a great story of friends, enemies and intrigue.

I think you will enjoy it, whatever your age.