IMO you should not coach her to do either. I shoot left handed. But I am ambidextrous. I can just as easily(but not as accurately) shoot right handed. I bat right handed. I do different things different ways.

But the bottom line to good accurate shooting is the dominant eye. You need to determine which of her eyes is dominant. Then you want her to learn how to shoot with that dominat eye. It is a mistake to teach her to shoot with the non-dominant eye. Yes she will be able to do it. But if you really want her to learn the proper way then let her use her dominant eye, and just accept it.

Let her shoulder a properly fitted firearm on her left side, and her right side then watch her eyes. You will easily be able to tell which is dominant.

My best friend has been trying to force his left handed son to shoot right handed for close to two years. In 30 minutes a couple of weeks ago I had him shooting better than he ever has shot only by using my left handed rifle, and teaching him to shoot properly with his dominant eye. Tom.