What is a girl dressmaker called?

The nouns 'dressmaker' and 'tailor' are common gender nouns.

The noun 'dressmaker' is a Word for a person who makes women's wear.

The noun 'tailor' is Word for a person who tailors men's and women's wear.

There are a number of other terms in the clothing industry such as modiste, custom clothier, designers, pattern makers, etc. All of which are common gender nouns.