I called crystal concierge and was told (after she confirmed and called me back) Visa allows 7 business day after the 1st of the year for posting to receive credits for the current year. So my guess is you will still get credits for this year if you make a purchase today. I made one on 12/29 and still waiting for it to post too.
this could also explain why posting at the beginning of the year is slow for purchases made after 1/1.