File NOW
Hi AC,
You should definitely try very hard to file before the end of October - your priority date is current, but only just, so if the dates for November retrogress even a few weeks, you won't be able to file. Once you've filed, though, even if they do retrogress, you are still considered "pending AOS" status, so you enjoy all the benefits of that status (EAD, AC-21 protection to change jobs after 6 months from filing, etc). Also, they can start the background check sooner rather than later. Hopefully the priority dates move forward, not backward, but you never know, and it's better to file and be on the safe side.
Good luck!