include different navigations in php

this is my first question here and my problem is that I want to display two different navigation headers depending on if you're logged in or not. I am confused as to why this goes into the if-statement and displays "you are logged in."

if(isset($_SESSION['user'])){
   echo "you are logged in.";
}

... but if I use this piece of code at the start of my page:

if(isset($_SESSION['user'])){
    include 'navbar-other.php';
}
else {
    include 'navbar.php';
}

It goes into the else case instead and displays navbar.php rather than navbar-other.php. This all implies that I am logged in and the $_SESSION variable is getting processed due to the first if-statement giving the desired output.
Is there a way to resolve this issue?