Hello! My name is Daniel and I fit all of your requirement quite handily though I do have experience. I have worked on the graphics end of many projects in the exact capacity you describe (graphic designing, graphic editing, element/assets/UI creation and mock up).
I am self motivated and able to grasp what is needed without being overly instructed though I always make sure to understand what is needed. I have worked closely with lead designer and programmers.
Hope to hear back from you. If you have any questions feel free to ask!
Regards,
Daniel