The first two make her look like she's an amputee. I think if you had moved a little bit to the side, this one would've been really nice. #3 would look nicer if you cropped off a little bit more of the right side.
my brother did my "senior pictures" almost 7 years ago. i think he ended up taking a roll of film, if not more. most of them turned out very well, and i think i was his first "real" portrait work outside. never made many prints though, just enough for my mom LOL
1 and 2 look a bit washed out, maybe you want to meter on her face instead? i dont know i havnt gotten into that much (yep i better go find me a book on metering )
well have fun, if you have a digital, at least you can do a LOT of playing around!!!
I like your choice of locations, and I think they can work well for you. Posing didn't come naturally to me either, and it's something I still struggle with. I spent a lot of time browsing websites of other photographers, reading books and just trying different ideas.