Crisp and preppy! Original Penguin shirt

I got this top at the Penguin boutique opposite Bryant Park in NYC. It’s a fresh and preppy basic. Great for office. How cute would it be under a pinafore-type dress or with a plaid skirt? The size is almost illegible on the label but I am listing as small. Please see measurement photos and ask me for more info to be certain of the fit. Off-white/cream. All buttons including the spare button are intact. Slight scuff on the back of left shoulder, see photo. Otherwise, very good used condition!