Datepicker - Newbie Question

Datepicker - Newbie Question

Hello there!

I am brand new to jQuery. I am trying out the "test" example...and I can't get it to work. I'm so frustrated because it seems so simple!

So it's the Datepicker example. 

Here is my page: 

I have all of the jQuery files loaded on my web host.

Here is the code below:
===============
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>First jQuery-Enabled Page</title>        
    
<link rel="stylesheet" href="jquery-ui.min.css">
<script src="external/jquery/jquery.js"></script>
<script src="jquery-ui.min.js"></script>   

    
<script type="text/javascript">
$( "#date" ).datepicker();
</script>          
</head>

<body>
<input type="text" name="date" id="date">
</body>
</html>
===============

I'm not sure what I'm doing wrong?
I'd be very appreciative if anyone could help me. 

Thank you,
Andrea  :)