I don’t see why this question is offensive.
If I ask: how many rooms do you have in your apt, is that wrong? It’s interesting to know and that’s it.
If you feel totally comfortable with it, then you should feel comfortable answering. Besides if the question is a breech in privacy. But here, it’s an ok question and shouldn’t offend anyone.
(And just as a side note, if someone asks me whether I have internet at home, I am embarrassed to say yes.)