How to compute AGE from DOB

1. I have a query that lists users from a table. One of the table columns is Date of Birth

2. On the page I display the list, I want an additional column that will show a computed AGE of each user from the DoB in the table.

3. Based on the computed Age, I want to add another column that shows a Qualified or Disqualified Status.

How do I achieve this?