I like both of these, particularly the black and white. I like that she isn't looking at the camera as is typically expected in a senior portrait. Her posture and expression seem very believable for her age. I even like that you've left some flyaway hair to capture the breeze. If I'm going to nitpick, it's that I don't have a good feel for how she's supporting herself. We see the wood (bench? fence?) only on one side of her; her pants are so dark that it's not obvious at first glance whether she's standing or somewhat sitting up on the wood (it's a little more obvious when I look closely, it just doesn't stand out as easily as the rest of the details in the shot). Now, I don't think that really hurts the image, particularly for someone who isn't trying to constructively critically dissect the shot.
I like the composition of the color shot, I think capturing her hair flowing off to the side is a nice touch that she may look back on fondly. I personally like that you let the "wild" ends of her hair go out of focus; I think it would also have worked well with a deeper depth of focus to bring all (or at least most) of her hair sharp, though it's probably a fine enough line to hit to get the hair sharp while leaving the grass OOF (which I agree with) that it's not worth the time dialing in during a senior shoot. My biggest nit pick about this one is that it might be cropped just a hair too tightly - how tight will it feel (particularly above her face) if you lose some of the border to a picture frame? I also may have considered (or asked her about) 'shopping out her tan lines. I understand about not adding excessive editing time, and there is a difference between removing them from this one shot versus having to do so for a whole set, I just think that without the tan lines this shot becomes much more timeless. Or, should I say, more indicative of this time in her life than of the top she wore one sunny day.
For someone who claims to need to work on his portraits I think these are pretty solid! Thanks for sharing.