Security issue - redirect

[eluser]Unknown[/eluser]
I am currently developing a cms system and I have coded my own simple Auth library.
Nothing fancy, but I wanted to check if things are secure enough.

When a user logs in, the lib sets some session attributes. One of them is "isLoggedIn" set to TRUE. This one I use in the "checkIfLoggedIn()" function.
Now; I have made a function which also checks if the user has logged in and if not; does a redirect to the login page:

Code:

function checkLogin() {
   if(!$this->isLoggedIn()) {
      $CI =& get_instance();
            
      $CI->load->helper('url');
      redirect('admin/login', 'refresh');
   }
}

On the page I want to secure I use this: (controller)

Code:

function index() {
   $this->load->library('authLib');

   $this->authLib->checkLogin();
        
    echo "Here goes the rest of the code if you have logged in.";
}

Is this way of working secure enough or do I need to provide some extra security?