"Corinna is not a girl, but a woman."
Translation:Corinna non est puella, sed femina est.
There is a verb (sum, esse, fui, futurus) that is basically a bunch kv different forms of the word 'be'. if you congigate in the present tense: Singular. Plural Sum(I am) Sumus (we are) Es. (You are Estis. (You are Est. (He/she/it is Sunt (they are)
you will see 'es' is the 2nd person singular of the present tense. Sum is an irregular verb so not all of them are congigated like this (in fact there are 5 different congigations of verbs all of them have different rules to break them down into different tenses) But the way each part is translated just goes along with the pronoun that goes with that part of the verb. So like the 1st person singular will go with 'I' because that's the 1st person singular pronoun. And its just a matter of how English is because if you say you is that doesn't make sence so its you are. Also keep in mind the pronoun will typically be a reflection of the subject of the sentence. I hope this helps!! One last thing idk if they gonna teach it to the little details so im not really sire its going to teach it right. There is a lot of things that go into this language and if you're intrested in taking this language further i think classes with an actual person would be better, or im sure there are other things like textbooks/youtube videos.
See the course introduction: https://www.duolingo.com/skill/la/Introduction/tips-and-notes
There's nothing wrong with your rendition. Sometimes not all possible word orders are accounted for on Duolingo. Do note, though, that in copulative clauses ("X is Y") est tends to come in the middle. When a verb is repeated in a subsequent clause, it is regularly omitted:
Corinna nōn est puella, sed femina.