CASTLEBERRY White Blouse with Scarf for Neckline Bow

Lovely dressy blouse in very good condition 21" across the chest 25" in length Sleeves are 24" from the top of the sleeve with 2 buttons Tag says a size 12 however my measurement across the underarms indicates that this may be wrong Please check the measurement with an item at home. Fabric: Unmarked, but my best guess is 100% polyester satin. no stretch.