A Mermaid Adventures story by C. L. Savage, the first book in the series. Here’s the introductory quote from the back cover:
It was the quiet after the storm. I sat up in bed – what had awakened me? I tried to sit still to listen, but my heart was pounding. Throwing off the covers I turned to look out at the rising moon shining brilliantly through the departing storm clouds, its silver lighting up my room.
Goosebumps rose on my arms and I tried to rub them down. At the gym pool, I peered down from the diving board, watching as the rising moon cast its light upon the water. Moonlight trailed into the water and bubbles began to rise from the bottom, the pool thrilling to the moonlight as its water called to me.
Caught up in the moonlight’s song, I dove in an arc into the still waters, shattering the moon’s reflection. Blissful waters greeted me, calling to me as one of its own. It was a thrilling experience as instead of the expected pool bottom, a sparkling undersea vista welcomed me.