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.
ей как раз literally means "to her, [it's] like 'bang!' [fits perfectly]". Apart from 'once', 'times', "раз" is used as an interjection similar to "Bang!" or "Wack!". The word is related to the verbs поразить (to strike) and сразить (to defeat by striking) and distantly related to рез- in резать (to cut).