Start to fill out the form before a full year (and submit once I had ILR for a year)

Hi everyone!

I would have been with ILR for a year next month, but I want to make sure that I fill in the form and prepare my application before (but submit it later after it has been a year here), can I do that? is there a problem if I start my application online ahead of time? or do they take the date of submission instead of the date of starting of application?

Thanks

The relevant date is when you submit/pay - not when you start inputting the application.
There is a time limit until the account expires but I believe that is more than a month.
So no issue starting early.