I'm going to have to disagree with Dave on this one. The BM-800 is a large side address condenser and is unsuitable for any use other than on a mic stand (which is pretty unusual for karaoke). It's also going to be far more prone to feedback problems since you're using this with a home audio system rather than a true PA system
Go with a cheap dynamic like a Thomann T.bone. Handling noise won't be THAT bad (and way better than the BM-800 if she tries to take it out of the shock mount and hand hold it) and it will be much better for feedback rejection while your daughter rocks it out in typical karaoke manner.