If you need to know the age of something and you have a start date, you can use a formula in Excel to calculate the age in the year, month and day format.
Open the file that has the listing of dates. For demonstration purposes, the dates are in Column A and the age results are displayed in Column B.
Copy and paste the following formula into Cell B2 and fill down:
\=DATEDIF(A2,TODAY(),"y")&" years "&DATEDIF(A2,TODAY(),"ym")&" months "&DATEDIF(A2,TODAY(),"md")&" days"
Look at the results. The result will show the difference from the current date to include the number of years, months and days. The best news is that you don't have to update the formula if you open the file at a later date; the age will automatically recalculate based on the current date.
To sort the ages, use the Birthday column and select "Ascending" or "Descending" order.