A common problem in coaching is assuming kids *actually* believe what we tell them because they politely nod every time we explain things. Try making her explain the key elements and why they are key to the skill. It usually doesn't take much time to get to the point where they expose the problem they're having, and why.
It wouldn't surprise me at all if this kid thinks her legs, or feet will not follow the rest of her body through the air unless she lifts them into the skill, and she'll continue to do some variation of a Frankenspring that caters to that notion until you convince her to follow the correct model of the skill.
The way she's lifting her legs seems, to me, to be her attempt to help her body get upside down following the logic that if her legs go up and over she'll cause her upper body to go down and under. It's really pretty sound logic, but it fails to consider the need for traveling backward with enough energy, with a stretched body that curves slightly in her upper back and shoulders to help her move through the handstand phase of the skill. I doubt you can get a beginner to swallow that concept whole, and even if you can, she'll lack the strength and awareness during her take off to make it happen just the way it should be, but she'll progress most easily by getting her as close to that model as the two of you can.
If you use drills, consider them as bit size pieces of the mental model she can't swallow in one bite, and convince her that she needs to incorporate those bites into the skill.