Proportions

can be very difficult to master. The hands and wrists are too big and theres something wrong with the face to neck structure. But, it's a step on the ladder. You have captured the lighting quite well so the basics are there. Practice and fine tune your skills and become an art god. Good luck with the art class.

good

sometimes it works just to not draw a face. that is the first thing someone will look at ( right after the boobs ). So if you do put a lot of effort into it. Good Work.

Some advice.

Make better use of the negative space. Not many works on here do that and they suffer for it. I also agree with Lonelyal3x, the proportions can use a bit more work here. Those hands and the left leg are bugging me a bit, and the face is a little flat.
Otherwise, great job, especially as an entry piece to a course. It shows that you have not only some talent, but some room for improvement.

One more thing I want to add, but only as a personal preference. Try using some different medias in your art. You won't find many pieces in a gallery with "photoshop" as the media used.

you an art student?

i went to an art school, and we had nude figure drawing... i learned from experience that proportions and details are vital but very tedious. if you can fine tune your work, your images will be amazing. best of luck!