While Soitgoes is correct that priviledges do begin as soon as one qualifies, AGR has a habit of not sending out kits for those who qualify during the last two or three months of the year.
And while one's qualification is based upon the calendar year, the actual year for the Status is from March 1st through the last day of February of the following year. So while you've qualified for status for the last two months of this AGR year, it is unlikely that you'll get a kit prior to mid-February when AGR mails out the kits for the year of March 1, 2008 to February 28, 2009.
You will however immediately start getting the 50% bonus points on any trips taken during the current month and next month, even though you won't have a card to prove your Select + status. And I sure wouldn't count on getting any coupons before you receive the kit. Even if you do get lucky, note that they will expire on Feb 29th, 2008. The coupons in the kit will run from March to Feb 2009.