Geek Code age auto-updater

.htaccess

RewriteEngine on
RewriteBase / 
RewriteRule ^geekcode.txt geekcode.php [L] # geek code
# people usually place their Geek Code in a txt file, so this silently redirects geekcode.txt to geekcode.php.
# if you already have RewriteEngine and RewriteBase set in your .htaccess, just place the RewriteRule directly below them.

geekcode.php

<?php
  header('Content-type: text/plain');
  
  date_default_timezone_set('America/New_York'); // for all intents and purposes you don't need this, but PHP throws a nasty warning if it's not included

  // for the record I don't know PHP. I stole most of this from http://stackoverflow.com/a/3776843 and winged the rest

  //date in mm/dd/yyyy format; or it can be in other formats as well
  $birthDate = '04/18/2001';  // set your birthdate here
  //explode the date to get month, day and year
  $birthDate = explode('/', $birthDate);
  //get age from date or birthdate
  $age = (date('md', date('U', mktime(0, 0, 0, $birthDate[0], $birthDate[1], $birthDate[2]))) > date('md')
    ? ((date('Y') - $birthDate[2]) - 1)
    : (date('Y') - $birthDate[2]));
  if ($age <= 9) {
      $gcage = '-----';
  } elseif ($age >= 10 && $age <= 14) {
      $gcage = '----';
  } elseif ($age >= 15 && $age <= 19) {
      $gcage = '---';
  } elseif ($age >= 20 && $age <= 24) {
      $gcage = '--';
  } elseif ($age >= 25 && $age <= 29) {
      $gcage = '-';
  } elseif ($age >= 30 && $age <= 39) {
      $gcage = '';
  } elseif ($age >= 40 && $age <= 49) {
      $gcage = '+';
  } elseif ($age >= 50 && $age <= 59) {
      $gcage = '++';
  } elseif ($age >= 60) {
      $gcage = '+++';
  } else {
      $gcage = '?';  // immortal
  }
?>
-----BEGIN GEEK CODE BLOCK-----
Version: 3.1
your geek code here, but replace a---- or whatever with a<?php echo $gcage ?>
------END GEEK CODE BLOCK------