If you want to know, just out of curiosity, it probably is not any of your business and would be offensive to ask.
However; if you are dating this lady, and they two of you are involved maybe taking it to the next level?
Ask how she feels about it? That will get the best result, quickly. If she is adamantly opposed to porn, apologize and move on to another topic, maybe as things progress she will lighten up her perspective, hard to say. Best wishes to you on that one.
Take care!