Vintage handmade blue blouse

Made by my Mother for me in the 80's or 90's. It is a washable synthetic fabric measuring 27.5" long, 25.5" across the chest under the arm seam. The fitted waist measures 18" across the front; has a 14" neck. 5 covered buttons on the back & 1 at each cuff. Light shoulder padding could be removed. Small spot (per pic) on the front near the waist. Sleeves measure 26". Size 10 or 12?