Answer:
Since Ruby was born in Puerto Rico, a U.S. territory, she naturally became a citizen of the country when she was born. The Mexican citizenship regulations, including any prospective citizenship by descent or through her parents, would determine if she also holds Mexican citizenship. But if she was born in the US I would say she's half Mexican because of her parents and she's half American too. If she lives in the US then her home town would probably be somewhere in Mexico