Numbers won't sort DATES correctly

I cannot get the column to sort the dates correctly in Numbers! ... I want to sort the column by date and instead of sorting 1 through 12, it sorts like this: 1,10,11,12,2,3,etc.

On the drop down menu under the Format tab, I select "Sort by: Date" but then the next drop-down only gives you the option of Ascending (1,2,3...) or Descending (3,2,1...) but it doesn't recognize the difference between a 1 and a 10 in front of the / (forward slash)