odd while behavior...

Okay so I'm just playing around with some stuff trying to learn more and expand my knowledge and I ran into something I don't understand... Take the following code: <?PHP echo "<select>"; $i ="0";

    while($i <="12") {

    $dateformat = date("M", mktime(0,0,0, $i,0,0));
    $month = mktime(0,0,0, $i,0,0);
    //echo date("M", mktime(0,0,0, $i,0,0));
    //echo "<br>inside while<br>";
    echo <<<HTML
    <option value="{$i}">{$dateformat} {$i}</option>

HTML;

    $i++;
    }

echo "</select>"; ?> which does display a select drop down box with the month's in it... But on my test server it starts the display at december... With setting $i = "1" i would have thought it should start at january? Any ideas on what I missed? :) Thanks for looking! :)