A note on parrying:
The object of a parry is not to stop an opponents stroke, but instead to slightly adjust the trajectory of that stroke, hopefully so that the weapon passes through an area not occupied by your flesh. It is reliant on creating angles more than anything. As such, a thin bladed weapon strong enough not to break or bow is more than capable of parrying an axe haft.
Note the placement of the damosel's feet and blade. If we were to see this axe stroke to the end, it would likely end up on the ground a few inches from her right knee.
As for a tight grip versus a loose grip, it is actually better to have a loose grip than a tight one with your fulcrum hand. Your other hand then controls where the blade goes, using it as a big lever. Ideally, your fulcrum hand (the one higher on the grip) will look like an "A-OK" sign, with the index finger and thumb forming a circle. The other fingers can rest gently without supplying a great deal of pressure - they are there to help with the bottom hand's movements.
Ideally, the damosel would allow the axe to slide off the blade during the orc's follow through and then simply bring the blade around to chop at the right side of the orc's neck, just above the shoulder - this would be the most natural recovery stroke.
In other words, I think its just fine!
[Edit: I just looked at it again and noticed that it might be more accurate if the damosel stepped into the orc a bit more - usually this kind of parry takes place immediately over the head of the person doing a parry. Of course, then her hands would obscure her face from your chosen angle.]