To clear up any questions you may have regarding the 2013 date of the Solemnity of the Immaculate Conception, please see the excerpt below from the USCCB Office of Divine Worship:
Solemnity of the Immaculate Conception in 2013
In this year of 2013, December 8—normally the Solemnity of the Immaculate Conception—falls on the Second Sunday of Advent. In accordance with no. 5 of the Universal Norms on the Liturgical Year and the Calendar, the observance of the Solemnity is transferred to Monday, December 9. Such a transfer is seen as a pastoral concession to the desire of the faithful to observe a beloved Feast even though it is impeded liturgically by a higher observance. The obligation of the faithful to attend Mass remains attached to the day itself (December 8), however, and so it does not transfer with the liturgical observance.
The Bishops in Europe, however, including the Bishop of Rome, will keep Sunday, December 8 as the Solemnity of the Immaculate Conception. Since MI Youth has received requests from MIs in Europe as well as the United States who wish to participate in the e-novena, we will send the daily prayers for the novena from November 29-December 7. For those following the USCCB's calendar, please note that the novena for you would begin on November 30. Simply follow "Day One," "Day Two," "Day Three," respectively, consistent with when you begin and end your novena.