I think you were wise to stop with this revision. It was an assigment, not a story on deadline with a publisher. You did very well meeting the goals of this task and have expanded your writing skills, too.
Or you may look back on it and say, "Wow, my first story writing as a female sub. I did very well on this!"I am sure that in a few years I will look back at this story and wonder why I did not do this or that. Untill then, we will have to be satisfied with what is.
I am more than satisfied with the time, effort and progress you made with this story.
Keep up the great work!