#REF! Error when Filtering Data

[astrophys]

When I filter my data for a certain column, I receive a #REF ! error randomly for one of my columns (Column C). I use other formulas within the other columns and they sort fine. Column C uses the INT function to calculate one's age as shown below:

To calculate Column C (Age), the formula used is: INT(E1-D2)/365

Should I be using another formula to calculate the age? For today's date the formula use =TODAY()
[TABLE="class: outer_border, width: 500"]
<tbody>[TR]
[TD]Rank[/TD]
[TD]Name[/TD]
[TD]Age[/TD]
[TD]DOB[/TD]
[TD]8/4/2017[/TD]
[/TR]
[TR]
[TD]1[/TD]
[TD]Mickey[/TD]
[TD]24.0[/TD]
[TD]8/21/1993[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]2[/TD]
[TD]Minnie[/TD]
[TD]24.8[/TD]
[TD]11/5/1992[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]3[/TD]
[TD]Donald[/TD]
[TD]29.1[/TD]
[TD]7/10/1988[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]4[/TD]
[TD]Goofy[/TD]
[TD]28.5[/TD]
[TD]2/8/1989[/TD]
[TD][/TD]
[/TR]
[TR]
[TD]5[/TD]
[TD]Pluto[/TD]
[TD]23.1[/TD]
[TD]6/17/1994[/TD]
[TD][/TD]
[/TR]
</tbody>[/TABLE]

 

[Derek Brown]

Try =TODAY() in E1
and the following formula in C2:
=DATEDIF(D2,$E$1,"Y")
For further information see:
DATEDIF function - Office Support
That will show you how to calculate the extra months etc.