Questions about Expiring date ?

I still haven't renewed my DACA it expires on January 1st 2016 so i only have about 1 month left. My question is will they deny my renewal because i haven't sent the renewal 3 months earlier of the expiration date or i am okay? Also after it expires on the date can i still send my renewal documents in or it will be to late? Thanks!

They won't deny it. You will however lose daca status until your application for renewal is complete.
That will take several months.