PHP age calculator / Alter berechnen

<?php
/**
* age_calculator()
*
* @param int $day DD
* @param int $month MM
* @param int $year YYYY
* @return int $age years
*/
function age_calculator($day,$month,$year){
if(date("n") > $month){
$age = (date("Y") - $year);
}
elseif(date("n") == $month){
if(date("j") < $day){
$age = (date("Y") - $year) - 1;
}
else
{
$age = (date("Y") - $year);
}
}
else
{
$age = (date("Y") - $year) - 1;
}

return $age;
}
?>