You're right, the jaw is a bit squareish... I've never drawn from a photo before, so this was a new experience for me. However - and you can't tell this from the scan, when I upped the contrast for the pic, it made all of my lines look like I'd lined them in. The pencil version is more of a 'barely there' look, and no soldity to any of those lines except her hair and eyes.
The scan simply does this piece no justice, and, I suppose my dad will be the only one who will get to really apprecaite it. Thank you so much for the lovely comments though, it makes me happy to see people putting thought into what they've written, and giving me that insight where I'm unable to distinguish mistakes.
Nice job. I know a girl who also loves to sketch Audery Hepburn, but you did a better job in capturing her character. Her jaw looks a little too square and the contours leading from her nose to her eyes are too much like outlines, but other than that I don't see any real flaws. I like how the dress is sort of there, but not really, because it kind of fades away into nothing, it is really effective. The detail of those few flowers on it also adds to the picture.