If your database of talent grows it is very likely that your cron will time out with all the queries that would need to be performed to update every age. For a large DB your cron would need to be set up on the server, no by using WP cron functions and would also likely need to be created in a way that checks how long it’s been running or is some other way be built so that the task can be done over several cron calls.
I would still use the date field. Let’s say that someone wants to only see people that are over 30 or over.
// format a date to string to search for
$query_date = date('Ymd', strtotime('-30 Years'));
then the meta query
$meta_query = array(
array(
'key' => 'date_of_birth',
'value' => $query_date,
'compare' '<='
)
)
