In the translation, the "and" means something closer to "I am a girl, and [what about] you?", rather than "I am a girl, and [I presume so are] you?". Specifically, saying «а ты?» redirects the question at the other party, without implying that you expect one type of answer over another.
My brother's Romani. And though this term might be taken poorly, he accepts it as a term of self-identification. I tend to discourage people from using it as a term for the Romani people as well (in fact, I have on Duolingo); but the word "gyp" as a verb has become so abstracted from its history that I no longer perceive it as rude or vulgar, but simply as colloquial and generally understood (Much like people can say that something "sucks" or that they are "saved by the bell"). It is only rude when dealing with the exceptional person who understands its history and assumes that I, as the speaker, also understand that history and purposefully employ it to be derogatory. Take the word "slave" related to the word "Slav;" is slave derogatory? Take the word "robot" from a Slavic root meaning "Slavic serf, worker, especially slave laborer;" Is robot racist? Let words be understood as they are meant to be understood by their speaker.
Enjoy your day! :)
You are close but missing one necessary word - "a." We must say, "I am a girl, and you?" If you input that, it will accept it. In English, in instances of describing ourselves with nouns, we utilize either the indefinite article (a or an, depending on whether the next word starts with a vowel sound), or the definite article (the). So you could say, "I am a girl, and you?" or, "I am the girl." The second sentence would be less likely to be used with "and you?" at the end, because acknowledging oneself as "the girl" indicates that you are the specific girl someone has been looking for, and a return query of, "and you?" would be quite unnecessary.