Responses
I'm replying to myself since I just noticed the second half of my comment was deleted (?)
Most Japanese drink tea with no sweeteners, so honey in tea is not an inherently known fact. Again, should be common sense since honey=sugar, but if you never put sugar in your tea in the first place, then one can see how it can be surprising.
It's not farfetched for her not to know about honey in tea (although it shouldn't be THAT much of a surprise)