Chico's Elegant Tan Blazer Runs small. I compared it to a sz 12

Sophisticated tan blazer by Chico's. Features a sleek, tailored design. Ideal for both professional and casual settings. The fabric is a rayon blend. Looks like wool. Fully lined. The front closes with large hook and eyes.which are hidden on the inside. Measurements are. Across the back shoulders about 16 3/4”. The total length from shoulders to hem measures about 25”. It falls just below the waist. The pit to pit flatfold measures about 19 1/2”. The hips flatfold measures about 20”. No visible flaws other than the size Please ask questions. And we will try to answer