Skin tones seem a bit cool and slightly yellow-tinged to me. I'd crop #2 down some...all that empty space seems a bit odd. The last one looks a bit over-flashed to me. Looking at these larger, and closely, I can see a slight bit of blurring due to the flash and ambient exposures being so close to one another, and her moving very slightly during the shots. As far as emotion and expression, she seems pretty good for a h.s. senior. I've seen much,much worse photos, and these seem to be somewhat like what I think a lot of today's kids would think would be senior photos.
Here are some very quickie Lightroom color adjustments, with a vignette added to #1 (the seated pose with boot extended) and the second shot, the one with the trees overhead...instead of cropping it, I tried to show the forest canopy as a background element. In the third shot, you can clearly see the warmer, less-yellow skin tone I went for. The last shot, the one with her arms folded at the knees, still looks a bit too yellow to me. On all of your originals, I thought you had over-exposed the highlights, so I used Recovery on those, as well as a bit of exposure correction, then a bit of contrast or clarity and black point adjustment.