سلام طبق اموزش جلو زفتم ولی با این خطا مواجه میشیم

 
include_once"connection.php";
// $_POST ,$_GET
$userdata = array(
    'fullname' => "mahdi zarra",
    'age' =>  21 ,
    'sex'=>'m' ,
    'isSingle' => 0
    
);
$sql = "insert into people
(fullname,age,sex,) values
('{$userdata['fullname']}',{$userdata['age']},'{$userdata['sex']}',{$userdata['isSingle']})";
//echo $sql;
if($mysqli->query($sql)){
    echo "User added successfully!" .PHP_EOL;
  }else{
    echo "Cannot add User($mysqli->error)!".PHP_EOL;
  }
eeror me 
PHP Fatal error:  Uncaught mysqli_sql_exception: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ') values
('mahdi zarra',21,'m',0)' at line 2 in C:\\xampp\\htdocs\\mysql\\mysqli\\insert.php:16
Stack trace:
#0 C:\\xampp\\htdocs\\mysql\\mysqli\\insert.php(16): mysqli->query('insert into peo...')
#1 {main}
  thrown in C:\\xampp\\htdocs\\mysql\\mysqli\\insert.php on line 16
Fatal error: Uncaught mysqli_sql_exception: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ') values
('mahdi zarra',21,'m',0)' at line 2 in C:\\xampp\\htdocs\\mysql\\mysqli\\insert.php:16
Stack trace:
#0 C:\\xampp\\htdocs\\mysql\\mysqli\\insert.php(16): mysqli->query('insert into peo...')
#1 {main}
  thrown in C:\\xampp\\htdocs\\mysql\\mysqli\\insert.php on line 16