I am not sure how much I exactly know about it, but I am not clearly left or right anything. I write right handed, but do many things, especially athletic things, left handed.
When I was in gymnastics as a child I clearly lead with my left even though my grip was stronger in my right.
Oddly enough, even when learning to read I could read right side up, wrong side up, from the back of the paper (if something was on a light box wrong side up I didn't realize it). The letters, words and sentences looked the same to me no matter how they were presented.
I was actually in driver's ed before I figured left and right out - and am still, over 20 years later, not always sure about it. I learned that left is up on the lever and right is down. Once the lever was moved I had to actually look at the signal in the car to see which way it was.
If she can work on developing strength in her left side it could make her more versatile and stronger. But that is just a guess.
I get a lot of this from my mom. She had the same left-right issues and can actually write forward with her right hand and backward with her left hand AT THE SAME TIME. And she used to be able to write different things with each hand as she did it.
Others will have suggestions to help this, I would think. Sorry I can't give more help.