In following example, as you can see in the photo, Find ages from date of birth can be identified by the YEARFRAC and TODAY, and INT functions.

=INT(YEARFRAC("1/1/2000",TODAY())) ----->>>>answer is 23
=INT(YEARFRAC("10/5/2010",TODAY())) ----->>>>answer is 12
=INT(YEARFRAC("11/9/2020",TODAY())) ----->>>>answer is 2
YEARFRAC Function
The YEARFRAC function is one of the Date & Time functions of Excel.
It Returns the year fraction representing the number of whole days between start_date and end date.
YEARFRAC arguments
1. End date section is a serial date number that represents the start date.
2. Start date section is a serial date number that represents the end date.
3. Basis section is the type of day count basis to use.