Am I wrong for being upset by this?

I had a drop in booking this morning, did a meet and greet and everything was going fine. I took a lap around the house to double check that the dog hadn’t gotten into anything overnight, when I was surprised by a man asleep in one of the rooms. The owner did not tell me anyone would be there and it seemed like she didn’t know he was there either. I couldn’t get in touch with her right away, so I ended the visit early. She eventually told me it was her son who had stayed there. I’m a woman and just from a safety perspective I was a little bit spooked. I haven’t cancelled my booking with her for tomorrow but I feel like I want to. She’s apologetic and sweet so I feel bad cancelling last minute. Am I wrong to be somewhat upset over this?