I agree with Rich. Not that you asked, but I would crop the front rock and right side between her boot and the brightly lit side-board. Do you hate uninvited advice? I don't usually give it. I'll blame Rich for encouraging me. Beautiful light, beautiful surroundings, beautiful youthfulness! All beautifully put together.
The light here in San Diego has been amazing this fall! Even on cloudless days the value range has been great for photography... While I agree a tighter crop to the sitter would be great but as an Environmental portrait I think the stepping stones to the subject are wonderful. This young lady is very much at piece and comfortable in her space. Either way this image works great.
she is a beautiful girl with a lovely smile, but I have to say that I like this one the best of the three. I'm not sure why, maybe I just like a little attitude. I agree with other comments about eliminating the foreground rock. You can crop it out and just keep her boots in the frame.