Congratulations on having the nerve to come back to a story over two years after the last update.
I saw in your author's note that you got some discouraging reviews. I'm in the process of writing my first fanfic, and have been surprised at how much reviews affect me. People forget that there's a difference between someone writing for fun, or as a writing exercise, and and maybe just starting out, and someone trying to be a serious or professional writer.
My one piece of advice is to not be afraid to edit your old entries.
As to the story, having just read the whole thing through instead of waiting two years, you will be pleased to know that I didn't notice any sort of jarring break at all between the third and fourth chapters. You just picked up where you left off, which is impressive.