I'm not fantastic at this, but an extra set of eyes can always be helpful. Here are the things that I noticed that were off a bit proportion wise. And of course this is based on what my own eye moves towards.
The arrows indicate points that needed to move a little bit one way or another.
The head was a bit on the shallow side, it just needs to be a bit bigger.
The breasts need a bit more shading to make them look more round like the models.
The right hand needs to have the knuckles turned out towards the camera more than you have them right now.
Her butt needs to expand a bit, the model has her back up off of the ground and has her weight on the right butt cheek.
But what you did so far isn't bad by any stretch, the lengths are mostly right, its just the masses that seem to need work.
Have you been doing the other exercises from term 1 that are aimed at getting all of the base shapes laid out in proportion? You can post them in here and track progress, I have been enjoying doing that personally.
I hope this all helps.