Well you might ask yourself that this is out to late for Christmas but is about the 12 days after Christmas is the ture meaning of the song.
I was going to put the whole explanation on all of the 12 days but by reading the first one you get it.
All of the text is from Wikipedia :
The 12 Days of Christmas is a period of time in Christian theology that marks the time between the birth of Christ and the arrival of the three wise men, also known as the Magi. The 12 days begin on Christmas Day (December 25) and end on January 6, also known as Epiphany or Three Kings' Day
The Twelve Days of Christmas" is an English Christmas carol. A classic example of a cumulative song, the lyrics detail a series of increasingly numerous gifts given to the speaker by their "true love" on each of the twelve days of Christmas (the twelve days that make up the Christmas season, starting with Christmas Day).[1][2] The carol, whose words were first published in England in the late eighteenth century, has a Roud Folk Song Index number of 68. A large number of different melodies have been associated with the song, of which the best known is derived from a 1909 arrangement of a traditional folk melody by English composer Frederic Austin.