I have three daughters, they all loved to see my knives, and would ask to do so often. In fact by or around that age they all had a knife of their own, which they could carry when we went hiking or camping. However, kids pick up stuff from all sorts of places, and at that age adults still sometimes talk about things in front of them as if they were still babies and weren't able to follow the conversation. It may be that your daughter has overheard people talking about an incident or about a film they've seen, or even heard her friends talking about such things, or seen news reports or whatever. Obviously, you need to talk to her about it, but if she is genuinely frightened or insecure because of your knives, maybe it'd be a good idea to adopt a more discreet form of carry until you've discussed it, and hopefully she sees things differently. As I'm sure you know, kids of that age also change their minds about things all the time. Good luck.