Size says Medium but fits like a small Women’s flannel shirt “Honey Bun”

Women’s flannel shirt says size medium but fits like a small “Honey Bun” Across neck: 6 inches Neck to shoulder: 6 inches Arm length: 23 inches long Pit to pit: 16 inches Back of neck to bottom: 25 inches Bottom across: 17 inches 2 pockets on front Button up Button sleeves Never worn