If your DD has fluorosis, you should be able to tell. There would have been white or brown spots on her teeth from the time they first came in. They wouldn't develop later.
I wouldn't recommend cooking with distilled water. Distilled water has absolutely no minerals in it, and it is TERRIBLE to drink or cook with for any extended period. It will make you seriously mineral deficient. If you're really worried, use bottled water or try a reverse osmosis system in your kitchen. If you do RO, you have to supplement with minerals, because it removes them all.
Humans have always ingested a little bit of fluoride, so I wouldn't be worried about your bottled water. I'm not in favor of fluoridated municipal water, but it's normal and natural to ingest some fluoride.
I wouldn't recommend cooking with distilled water. Distilled water has absolutely no minerals in it, and it is TERRIBLE to drink or cook with for any extended period. It will make you seriously mineral deficient. If you're really worried, use bottled water or try a reverse osmosis system in your kitchen. If you do RO, you have to supplement with minerals, because it removes them all.
Humans have always ingested a little bit of fluoride, so I wouldn't be worried about your bottled water. I'm not in favor of fluoridated municipal water, but it's normal and natural to ingest some fluoride.