As always, it depends on your insurer.
You definitely won't lose your NCB as you're not claiming. However, you will have to declare a non-fault accident at renewal time and they may choose to load your premium because of this. As always, ring and ask for clarification.
If you get on well with her and trust her 100% (and I mean proper 100%), then let her do it outside of the insurance. If you suspect foul play for even one second, then call your insurer and let them handle it.