My guess is that you didn't ask the question

at the interview for a reason - fearing that might negatively impact your chance of getting offered in the end. If that's the case, and you really want this job, just wait for a while, feel things out first. Ask the question later when you are more settled.

Also, it wasn't clear in your post whether you would just like to ask for their policy on working from home, or you would like to make a request for you to be able to work from home. If latter, given that you didn't negotiate earlier, you may have to wait a little while. Gather more info before making the request.