Puzzle of the Week #002 - Professor Layton and the Curious Village

When asked about her birthday, a young woman gives the following information:

"The day after tomorrow, I turn 22 , but I was still 19 on New Year's Day last year."

When is her birthday?

Have a hard time finding the solution for this puzzle? Try using these hints.

Hints :

Hint I
Hint II
Hint III

The answer of this puzzle will be revealed next week.Try to find it before then. Have a nice thinking time!