age calculation with non-traditional work sheet

Hi all and thanks to anyone willing to help.

My spreadsheet ends up with date of birth in C3 - C20, and I need it to calculate age for me and put that in D3 - D20 (for example).

I cannot figure out how to do this. All the examples are based on A1 and when i try to change for my fields I get some lovely message about having circular logic or something.

Is it hopeless? Can anyone help?

Thanks!

If you just want age in years use this formula in D3 and copy down to D20

=DATEDIF(C3,TODAY(),"y")