That depends on the situation and the lady. I laugh most of the time when someone does that to me, but there are times when it feels like I am being patronized and that ticks me off. If you think she is serious, then a serious answer is the best way to go, even if you think the question is silly.
It sounds like you're trying to settle a bet. Lol she was offended and you don't understand why and she said... Ask a girl and she'll understand. So... Here's my perspective. From a females point of view it could sound like you're being sarcastic or just blowing her off. But it's possible that you meant no harm. :-) good luck!