Hi, MrJed! I believe our daughters might be around the same age - mine is 2 1/2, and a challenge to keep still long enough to get in focus!
Also, I'm just throwing this out there: I think that some people (at least me, anyway) might be more hesitant to offer a critique on a photo of someone's child. I find it personally difficult to divorce myself from the emotional attachment I have of a photo of my daughter and to look at it through the eyes of a stranger.
That said, I have a couple of quibble with the composition. The one grey fence post is going directly into her head. Since it's the only grey thing in the frame, it's a bit distracting. Likewise the tiny bit of branch on the far right of the frame is nearly as bright as her dress and keeps drawing my eye, even though it adds nothing to the photo. A bit of cloning could fix both of those.
Speaking of bright parts, I wouldn't worry at all about the exposure of her dress. It's bright but not overexposed, and I personally prefer photos that have elements that hit both edges of the histogram. Probably the flash made the dress brighter than it would have been otherwise.
More importantly, I can't tell what the story of this photo is. Is she contemplative? Resting? Curious about something in the grass? Perhaps if you'd shot from a different angle - directly behind her, farther back, closer to the ground? - we could have been clued in more to the story. I too had a go with it in Lightroom, and I didn't know which direction to go with the processing.
I ended up with two versions - one warming up the white balance (I suspect your flash might have made it cooler than it would have been otherwise) and adding some vignetting, and one that has a darker, more ominous feel. In both instances, I cloned out those two parts I was referring to earlier.
Edit #1
Edit #2