The answer to a simple question can't be more confusing

Today, I met someone very interesting. I asked her where she was from. I thought she was Chinese like all the other Asians. How wrong was I!?
Her dad is British. Her mum is half Chinese, half Filipino. She was born in America. But she has been living in Dubai for the last 10 years. She has a British passport. Her first language is English and she speaks American English. She also knows Italian, French, Latin, Arabic.
                  WTF?
And she can't answer "I'm British" because she looks Chinese. No one would believe her. Including myself. :P
But we both agreed that it's annoying when everyone says "really?" when I say "I'm Japanese" and she says "I'm British."