Correndo o Escuro por Alaya Dawn Johnson. Primeiro na série Spirit Binders .
Encontrei isso por meio de um arquivo "Encontrar este livro" da Goodreads pergunta que combinava nos detalhes. Aqui estão trechos do post de solicitação da Goodreads:
[Searching for book:] magic fish with jewels, girl grows wings.
It starts out with our protagonist, a teenage girl, waking up to discover she's had her first period, and in her culture, that means she has to wash it off in the ocean when she dives for a fish that gives away a jewel for whatever reason, but she gets two jewels,because the fish is dying.
Later, something weird happens, I think the girl has an unspoken love for some religious novice, and then spends a night on an altar growing wings and then flies off to save the world?
E de críticas da Goodreads:
Lana meets her true [love], and he spirits her away to his stronghold.
[She is] seeking comfort with the water guardian.