pretty model but she looks a little too posed to look candid if that was what you were going for. It just looks like it would be uncomfortable. The foreground is well exposed but there is no detail at all in the shadows. Still not bad. Looks like something you would see in a brochure for a college.
You have some very good lighting there and subject matter is good and clean. Only nit pick I have is the BG side walk. It's not too bad but kind of distracting.
She is so pale :) I like the natural feel of this picture. I wish the colours were more vibrant. Probably you took this picture in the middle of the day. I would try evening light. It's more flattering to the people as well as to the plants :)