PHP Time Since Date

<?php
$eventTime = '2013-06-04 23:23:23';
$age = time() - strtotime($eventTime);
if (60 > $age) {
  echo ($age) . ' Seconds Ago';
  exit;
}
if (3600 > $age) {
  echo round($age / 60, 0) . ' Minutes Ago';
  exit;
}
if (86400 > $age) {
  echo round($age / 3600, 0) . ' Hours Ago';
  exit;
}
if ($age > 86400) {
  echo round($age / 86400, 0) . ' Days Ago';
  exit;
}
?>