[Excel 2013] Columns of a table shifting to the left

Hi,

I have a question concerning the formatting of a table :

In this table :
1) In B12:M12, in each cell, are the months of the year.

2) B12 has a drop down menu also with the months of the year.

3) Under each columns of de B12:M12, that is B13:B18 are values corresponding to the month.

4) I'm desperately looking for a way to, let say, if I select a month, February in the drop down, the values of february will shift from B13 to B12.

5) B13 will now show the values of March in cells bellow.

6) So, we can see that there's a shift of columns to the left.

The table must :

7) retain the same number of columns, i.e. 14;

8) If i select, February in the drop down, January will go right to the end of the table.
Example :
February March April May June ... December January
It's a carrousel like type of table. Get the picture ?

Here's a file showing what I'd like to do.

Thank you for your much appreciated answers ,

Camaalot