convert "March 27, 2018" to time and return time ago

function timeago($date){
   $timestamp = strtotime($date);  
   $strTime = array("second", "minute", "hour", "day", "month", "year");
   $length = array("60","60","24","30","12","10");
   $currentTime = time();
   if($currentTime >= $timestamp) {
     $diff     = time()- $timestamp;
     for($i = 0; $diff >= $length[$i] && $i < count($length)-1; $i++) {
       $diff = $diff / $length[$i];
     }
     $diff = round($diff);
     return $diff . " " . $strTime[$i] . "(s) ago ";
   }
 }