Creating an age filter page ?

I have a website for an acting agency, they’ve requested the actors age get calculated from their DOB automatically; I’ve accomplished this part with this simple PHP:

$current_year = date('Y');
$age = $current_year - $year_of_birth;

Now, I need users to be able to select an age range (18-30, 31-45, 46 <) and the posts populate the page accordingly…

I’ve got custom post-type female-talent
Custom field year_of_birth

I wanted to page a template that goes something like;

if ($age =< 30) {
} elseif ($age ...) {
} else ( ) {
}

Any ideas?
Thanks