Our Snowman Had Olive Eyes

I read this book as about a nine or ten year old (give or take), and it started a lifelong (so far) diary writing habit; a desire to record and interpret life. Or maybe it just tapped into an existing desire, I don't know. I re-read it at 36 and enjoyed it again. The book tells the story of a girl whose elderly maternal-grandmother comes to live with her family and share her room. The grandmother has a heart condition and the girl's mother wants to keep her quiet and un-busy, but the girl sees how unhappy this makes her grandmother. The book also touches on the girl's relationship with her older sister (whose diary she regularly steals reads of).