Typ nåt sånt här?
$years = date('Y', mktime(5, 1, 1, date("m") - 2, date("d") - 23, date("Y") - 2005));
$years = $years - 2000;
$months = date('n', mktime(5, 1, 1, date("m") - 2, date("d") - 23, date("Y") - 2005));
$days = date('j', mktime(5, 1, 1, date("m") - 2, date("d") - 23, date("Y") - 2005));
echo 'Antal år: ' . $years . "<br>\n";
echo 'Antal månader: ' . $months . "<br>\n";
echo 'Antal dagar: ' . $days . "<br>\n";