Black wool knit tube skirt, Medium (fits small?)

Black knit pencil skirt by D. Exterior in Size M. High waisted, knitted construction, slip-on style, pencil silhouette. Straight hem, no vent, mid-length.100% extra fine mid-weight wool, unlined. It's labelled as "M", but I think it's more like Small or Extra Small. Waist (flat) about 12 inches, hips (flat) 14 inches, length 25 inches. New, never worn, without tags. Please note that the brand label is off on one side.