Your fun has just started.
Look at the first three chapters. Look at the first sentence. Look at the first five pages.
Each of these are critical if you want to sell it. Do not even bother with a re-write of more than the first three chapters until you have an agent/publisher interested.
All of the above are what will keep you from getting into the slush pile/or rejection pile.
You know the genre so you need to identify the agents/publishers who might be interested in that genre. Find them.
Craft your synopsis and query letter.
When all of the above is done send letters and wait. With luck some agent might ask to see the first three chapters. If they do you can send that. If they ask for that then bust ass to get the rest in shape. Learn patience.
If you want to re-write the whole thing with your fingers crossed you'll at least have something to do. Sending queries and synopsis might be a better use of time and effort. Your time and effort.
But then this is what I do because I have friends who are published writers and this is what their agents advise. Same with the agents I know. Maybe others get other answers from their agents or their friends' agents.