Simple private user page

<?php

    session_start();

    $_SESSION['user_id'] = "2"; //THIS IS SET DURING LOGIN!

    if(!isset($_SESSION['user_id'])) { die("Not logged in!"); };

    $requested_user = $_GET['id'];

    $db = new PDO('mysql:host=localhost;dbname=testdb;charset=utf8', 'root', 'MyPassword');

    try {

        $stmt = $db->prepare("SELECT * FROM c_userpage WHERE id = ?");

        $stmt->execute(array($_SESSION['user_id']));

        $mydata = $stmt->fetch();

    } catch (Exception $e) {

        //error with mysql
        die();

    }

    echo "Hello! my name is {$mydata['username']}!\n";
    echo "About Me: {$mydata['custom_data']}";

?>