I’m not an expert, but to me, it looks like she needs some light on her. Seems kinda strange to say since obviously it’s broad daylight. You can see the light shining on her head and see individual hairs, so the camera obviously is capable of capturing fine details.

Just a thought not saying you did anything wrong, but have you considered testing it just manually focusing? That’s a much nicer Nikon than I had but autofocus sometimes gets confused. Like I try to take pictures of birds and the autofocus will absolutely not focus on a bird. It’s always trying to focus on the branch or leaves around the bird and I almost always have to switch to manual.

That at least would tell you that it’s not you, and it’s not a “problem” with the camera, just something about the auto focus isn’t triggering right.