Willow Smith is sad. Except she isn’t just locked in her room listening to Radiohead; she’s sampled the band’s song “Codex” (from 2011’s “The King of Limbs”) and put her vocals over a spare loop of its beats.

Released as a single about a week ago, Willow’s “Sugar and Spice” (the 12-year-old’s debut album is due this year), is good for such a young singer. Her unadorned voice has the vulnerability of a girl on the cusp of a major change.

Twelve was when The Cure and The Smiths clicked with something unsettled in me. I didn’t have much to be sad about. I was simply exploring the vastness of an expanding emotional palette, trying on romantic sadness.

Two years ago, Willow was all girl-power confidence: “Don’t let haters keep me off my grind/Keep my head up and I know I’ll be fine,” she sang on “Whip My Hair.” “Sugar and Spice” is a different kid: “Sad he’s always screaming at me/… I write circles in the sky while I’m drowning.”

She’s an artist exploring. And her diary is an open book. The song just makes me hope that she and everyone else muddling through age 12 has someone really listening to them, like Willow’s pleading for here.