rethinker is right on! way to rethink, he understood the correct form of the question, and came up with the correct answer! Way to rethink
On January 1: the day before yesterday I was 10 years old, but next year I will be thirteen years old....
December 31, 1994 was the date of your birth.
December 30, 2005 you were still 10.
On January 1, 2006, you are 11 years old.
You'll turn twelve on December 31, 2006.
And in the year 2007, you will turn 13... That is not to say that on January 1 you'll be 13, but rather to simply state the fact that you will be thirteen AT SOME POINT THAT YEAR.
Great fun ol' boy, thanks!