People
Kids think with their brains cracked wide open; becoming an adult, I’ve decided, is only a slow sewing shut.
— Jodi Picoult ‧ My Sister's Keeper

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The image treats a child's mind as wide open and growing up as a slow stitching shut. That reversal makes adulthood sound like a loss of possibility. The speaker pictures curiosity narrowing over time, rather than assuming that age always brings a broader view.
Context reviewed