I'm sure the above works fine, but I couldn't understand half of it. >_>
anyway, this is the way I would have done it.
<?php
$birthTime = mktime(0,0,0,11,27,1987);
$birthYear = strftime("%Y", $birthTime); //get's the birth year
$birthMonth = strftime("%m", $birthTime); //get's birth month
$currentYear = strftime( "%Y", time() ); //get's the current year
$currentMonth = strftime( "%m", time() ); //get's current month
$age = $currentYear - $birthYear; //your age
if ($birthMonth > $currentMonth)
$age--; //if your birth month hasn't past, you aren't a year older!
echo "You are ". $age . "year's old!";
?>