Magus said: Year of the Rabbit doesn't start until February 3.
Remember, the Chinese New Year is based on a different calendar system. So for 33 days, 2011 is the Year of the Tiger.
To clarify:
The Japanese New Year is based on the Gregorian (Western) Calendar and Jan 01 2011 is indeed the Year of the Rabbit.
The Japanese wikipedia defines 卯年 (Year of the Rabbit) as any year on the Gregorian calendar which has a remainder of 7 when divided by 12. (http://ja.wikipedia.org/wiki/%E5%8D%AF).
Kinda counterintuitive, but stuff like this happens when one switches from one calendar to another (Japanese Lunisolar to Gregorian) for celebrations.
(The Japanese Lunisolar Calendar is adapted from the Chinese Lunisolar Calendar, 'though there are still some slight differences.)
Shou is older than Gensoukyou though, and she was sealed in Makai for quite a while, so she may be using the Japanese Lunisolar Calendar for year reckoning instead.
