SOLVED. YA/ Children's fiction book written in acrostic style - the first word of every Poem's line tells a story (pre-2014?). [s]

[Brittany]

When My Sister Started Kissing maybe?

[Becca]

Hidden by Helen Frost? It's about two girls, Wren and Darra. It's written as poetry / novel in verse from Wren's perspective, but "For Darra’s dialogue, [Frost] created an ingenious form specifically for this novel. The last words of the long lines, read vertically down the right side of the page, form sentences that elucidate Darra’s memories", according to this interview - https://www.bookpage.com/interviews/8...