If you fulfill your residence period requirement on 1.11.2016, then you can apply for citizenship some time like 4 months before that (1.7.2016). Since the eligibility is assessed on the day the processing your application starts, you can hope that the requirements are fulfilled by the time the processing starts. Of course, there's no guarantee they wouldn't start the processing earlier, but it's unlikely.
That's all fine. In fact, some people here have told they did exactly that. They applied after 3 years and 8 months of being in Finland *, and their application was accepted. Well.. turns out there's a price for this.
Today, I went with a friend of mine to submit her early citizenship application (she needs help with her wheelchair). She's been here 3 years and 10 months. The lady at the counter accepted the application, took copies of the original documents, and gave her a receipt. Right at the end of the whole process, the lady tells her
This essentially means that my friend's attempt to get her citizenship 2 months earlier had actually result in her application being stretched probably 3-4 months. Live and learn.Keep in mind that you don't fulfill the requirements at this moment, so I made the preliminary decision that your application is incomplete, and thus it goes to the incomplete applications queue
* Don't get riled up. This 4 year thing is a completely separate matter.