Well done Secretary. For some reason I don't find your hostess's question particularly rude. But I didn't hear her tone of voice or see her body language. However, perhaps she was concerned for you? Or just curious? I understand it was a bit nosy, but I guess I would have been ok with the question. However, if she had insisted on your having a drink, I would have a different opinion.
But we all have our own boundaries, personally, I long ago stopped asking people why they weren't drinking. I've had more than a few friends who quit drinking after serious alcohol problems, so I've learned to just let non-drinker be non-drinkers without my questioning why. It's there business and no concern of mine.
Anyway, thank you for the encouragement.