Good on her, if she can do this now it will save you loads of stress re introducing bread, solids etc. with the worry about can she chew/swallow etc. Just go with the flow, it sounds like weaning made easy to me! Mine was 22 weeks and most people do well to get to 26 weeks. Don't stress for the sake of it.
I may be wrong but I had understood the rationale behind BLW to be that if a baby can pick food up, put it in its mouth and eat it on its own then the baby is physically capable of eating and digesting that food. Therefore I would not worry. Besides your baby helped itself to the food; what could be more "baby led" than that?