@armand.munteanu - Oh no: verbs, like "est", do not agree with the subject. The correct form is "la fille est ..." . If you edit your post I can delete this.
it's right "Et" means "and" but "est" is a word from the verb "Etre" (to be) and it never changes . La fille est belle. Le garçon est beau.
sorry armand.munteanu, you can beleive me, I am a French woman