You can use conditional formatting to colour the cells accordingly.

Assuming your dates are in column A beginning at A2, then select the range from A2 to bottom of range and go to Home|Conditional Formatting|New Rule.

Select "use a formula to determine which cells to format" then enter formula:

=DATEDIF($A2,TODAY(),"m")>=23

Click Format and choose from the Fill tab.

Click Ok, then New Rule and repeat with formula

=DATEDIF($A2,TODAY(),"m")>=11

and again with formula

=DATEDIF($A2,TODAY(),"m")>=5

Make sure the formula are displayed in the above order (you can move each up or down with the arrow tools), then check the "Stop if True" checkboxes in the last column.