These days the word кофточка is widely used as a synonym of блузка (a blouse - in the sense of a woman's upper garment). Strictly speaking, though, кофточка is a diminutive form of кофта, which means "cardigan". To older generations of Russians, кофточка only means "a little cardigan" and never a blouse. The garment is knitted and open in front.
"The gray blouse fits her perfectly" was marked wrong. Is a кофточка not a blouse and therefore a generic phrase for any garment worn on the upper body other than a jacket or coat? Or is "fits her perfectly" somehow wrong? Everyone I know uses the expression "fits perfectly," not "fits just right." The latter sounds like a line from Goldilocks and the Three Bears.