问题与PHP登录管理员

我有一个问题与我的代码，我的登录工作完美，但我希望它显示注册到网站的用户列表从mysql数据库当我登录为admin@admin.com我的凭据。我的代码显示了为网站注册的用户列表，但它显示了现在登录的每个人，而不仅仅是管理员。有人能看出我错过了什么吗?谢谢你！下面的代码。

    <?php
session_start();

$mysql_hostname = 'localhost';
$mysql_user = 'username';
$mysql_password = 'password';
$mysql_database = 'db_users2015';
$connect = mysql_connect($mysql_hostname, $mysql_user, $mysql_password)
or die ("Couldn't connect");
echo "<BR>Connection Successful";
  //to put data into database
  //select database
  $db_selected= mysql_select_db($mysql_database, $connect) 
  or die ("Couldn't connect to the database");
//frontend and backend data processing
  $email= $_POST['email'];
  $password= $_POST['password'];

//to check for admin
$sql= "SELECT * FROM users WHERE email= 'admin@admin.com' and password= 'password'";
$sql_result = mysql_query($sql);
  {echo
  $query = mysql_query("SELECT email FROM users");
  echo '<table>';
while($rowtwo = mysql_fetch_array($query)){
  echo '<tr>
        <td>' .$rowtwo['email'].'</td>
        </tr>';
}
echo '</table>';
} 

//To see if email is registered
$sql = "SELECT COUNT(*) FROM users WHERE email= '{$_POST['email']}'";
$sql_result = mysql_query($sql);
if (mysql_result($sql_result, 0)<1)
 {
die("<BR>Email address not found");
}
else{
    echo "Login Successful!";
}

//To check if email and password match
$result = mysql_query("SELECT * FROM users WHERE email = '$email' AND 
password ='$password' LIMIT 1");
if(mysql_num_rows($result) > 0){
  $row = mysql_fetch_array($result, MYSQL_ASSOC);
  $firstname = $row["firstname"];
  $lastname = $row["lastname"];
  echo "<BR>Welcome back, ";
  echo $firstname;
  echo " ";
  echo $lastname;
}else{   
  echo 'wrong password/username combo';
}
?>