PHP implementation of converting date to age

    /*
     * @param cheack age
     */
    function howOld($birth) {
        $birthday = strtotime($birth);//int strtotime ( string $time [, int $now ] )
        $year = date('Y', $birthday);
        if(($month = (date(&#39;m&#39;) - date(&#39;m&#39;, $birthday))) < 0){
            $year++;
        }else if ($month == 0 && date(&#39;d&#39;) - date(&#39;d&#39;, $birthday) < 0){
            $year++;
        }
        return date(&#39;Y&#39;) - $year;

    }

 $data["birthday"] = $this->howOld($birthday);
        var_dump($data["birthday"]);