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]
[TABLE="width: 990"]
<colgroup><col><col><col><col><col><col><col><col><col><col><col></colgroup><tbody>[TR]
[TD][TABLE="width: 500"]
<tbody>[TR]
[TD][/TD]
[TD]A[/TD]
[TD]B[/TD]
[TD]C[/TD]
[/TR]
[TR]
[TD]1[/TD]
[TD]Date[/TD]
[TD]Anniversary[/TD]
[TD]Years[/TD]
[/TR]
[TR]
[TD]2[/TD]
[TD][TABLE="width: 84"]
<colgroup><col></colgroup><tbody>[TR]
[TD]6/23/1997[/TD]
[/TR]
</tbody>[/TABLE]
[/TD]
[TD]6/23/2019[/TD]
[TD]21[/TD]
[/TR]
[TR]
[TD]3[/TD]
[TD]7/1/2001[/TD]
[TD]7/1/2019[/TD]
[TD]17[/TD]
[/TR]
[TR]
[TD]4[/TD]
[TD]7/6/2004[/TD]
[TD]7/6/2019[/TD]
[TD]14[/TD]
[/TR]
[TR]
[TD]5[/TD]
[TD]3/21/2016[/TD]
[TD]3/21/2019[/TD]
[TD]2[/TD]
[/TR]
</tbody>[/TABLE]

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[TD]Any assistance on how to complete this goal or a better way to do it would be appreciated.[/TD]
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</tbody>[/TABLE]

 

[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.