On the 25th of December.
25th December just like all churches in the Western Catholic or catholic derived tradition.
Mexicans are mostly Catholic, and they celebrate Christmas Day on December 25, which is a national holiday in Mexico.
In France, just like in America, if you are catholic then you do. 
yea, 90% of Ecuador is roman catholic
It began on the 25th of April 2000 years ago.
7th of january
Because most Mexicans are Roman Catholic (i.e.: they believe in Jesus, the Virgin Mary and the apostles). As such, they celebrate Christmas.
Same as Christan's everywhere, it is a catholic country, they celebrate Christmas with carols/church on the eve of the 24th, and on the 25, its a time for the family, Christmas lunches ect...
December 25
The date of Christmas is on 25th December
Not only can they. THEY DO AND SHOULD. The Catholic Church is the first Christian Church, and was the Church that STARTED Christmas celebrations. OF COURSE they celebrate Christmas!
January 6th in Ireland, January 1st in the Scottish highlands. It is the former Christmas before the Roman Catholic calendar was changed to include the pagan holidays. It is the date of the epiphany which is when the three wise men made it to Jerusalem. Hope this helps somewhat.