I am Over 18 Years of Age

<?php
session_start();
if ($_REQUEST["over18"] == 1) {
    $_SESSION["over18"] = 1;
    header("Location: " . $_REQUEST["redirect"]);
}
?>
<html>
    <head>
        <title>Verify Your Age</title>
    </head>
    <body>
        <a href="verify.php?over18=1&redirect=<?=$redirect?>">I am over 18</a> |
        <a href="http://www.google.com/">Get me out of here!</a>
    </body>
</html>