VBA or Formula to Calculate Years Between Dates and Highlight A Cell

[Evernight2021]

I have a spreadsheet with a column of dates (A) and anniversary dates (B). I want to make a column (C) with cells that calculate if the date in column B is equal to or greater than today's date. If so, I want them to subtract the date in column B1 from the date in A1 and put the number of years between them in C1 and then highlight the cell in a color to make the change stand out but I'm not sure what the best way to do this would be. I have the following formula that correctly calculates the years, but I can't figure out how to change the cell color when that value changes:

[FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]

[FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]=IF(N45<=TODAY(),ROUNDDOWN((N45-D45)/360,0),ROUNDDOWN((N45-D45)/360,0)-1)[/FONT]

An example of the data is below:
[/FONT]

A B C 1 Date Anniversary Years 2 6/23/1997 <colgroup><col></colgroup><tbody> </tbody> 6/23/2019 21 3 7/1/2001 7/1/2019 17 4 7/6/2004 7/6/2019 14 5 3/21/2016 3/21/2019 2 <tbody> </tbody>
Any assistance on how to complete this goal or a better way to do it would be appreciated.

<colgroup><col><col><col><col><col><col><col><col><col><col><col></colgroup><tbody>
</tbody>

 

[Evernight2021]

The formula should actually be

=IF(B1<=TODAY(),ROUNDDOWN((B1-A1)/365,0),ROUNDDOWN((B1-A1)/365,0)-1)

Forgot to modify it for the example.