The fit of the body is fine, I normally wear sz small and size small in this shirt fits fine on the body.  I emphasis on the body because the sleeves are about 2 inches too long.  The material is cotton, not the Gap Body kinda cotton...more like Walmart shirt cotton.

Overall this shirt if ok for the price, the thumbholes are plus but the fit of the thumbholes are a bit tight.

Also, the white color IS see thru so you WILL need to wear a tank top or camisole under neath.