A Very Good Question

The other day, a child approached me on the street and said hello. I of course responded with one or another of the customary responses to this greeting. But she--a dirt-smudged girl of about seven or so--went right on staring at me. I began to grow nervous, because you can never tell who might be a covert assassin or an undercover Avon salesbeing. I proceeded to watch the girl out of the corner of my eye and practicing various alarmed and/or frightened facial expressions, just in case I had need to put one on in a big hurry. When, after a few seconds she failed to produce a firearm or a sample case, I turned to face her again. Not knowing what else to do, I stared back, putting every square inch of my countenance into a look that would have made a schizophrenic wallaby twitch. The average adult would have lost neural function. Apparently children, owing to their fundamental insanity and their 90%-sugar body chemistry, are impervious to this. So, while I attempt to reassemble my facial features, this grubby little ragamuffin grins up at me and asks, deadpan, "Are you a Mexican?" This was precisely the sort of question that I, under no circumstances, would have anticipated being asked. I gaped at her in a manner similar to that in which a goldfish might gape at the north face of the Federal Reserve building. Eventually I managed to babble, "No." I am not, in fact, either a citizen of or descended from any peoples native to that nation. Nor have I, a rather distractingly average Caucasian, ever been mistaken for anything else, save a piece of furniture once. I was fairly surprised. The girl seemed to attach no particular importance to any answer I might have given, affecting a lack of concern that bordered on catatonia. She, apparently, was just curious.
I wonder what she'd have done if I'd said yes?