when does index run?

I have a controller that has a public function called index(). This calls my dashboard and in my dashboard I  have a javascript function that gets the user's email address. I use this email address to index many pieces of info about the user. I need to be sure that this dashboard is run very early in the process, right after $this->load->database(), but before anything else happens. 

I don't see where index() is being called? Should I pull the call to the dashboard out of the index() and place directly in __construct()?

proof that an old dog can learn new tricks