Problem with PHP 5.5 +

Suppose I have a link: http://www.mysite.com/index.php?id=123

In PHP 5.3 I can get and store the value of name & id easily like this way:

$myID = $_GET['id'];  // would return '123'
$myAge = $_GET['age'];

Code (markup):

No error gave me though there is not 'age' value in the url.

But in PHP 5.5 I can't use my previous code. It displaying error message like this:
Notice: Undefined index: age in E:\WEB\Server\xampp\htdocs\project\index.php on line 27

If I use 'isset' like the following way then it display no error message:

$myID = isset($_GET['id']);  // would return '123'
$myAge = isset($_GET['age']);

Code (markup):

But it store 1 & 0 for $myID & $myAge like true or false.

So how can I store values getting form url using GET method?

 

You can cast the value to an int. FALSE would cast as 0, while any other value unless it's been tampered with, would cast the the actual number. This would also prevent a lot of injection attacks.
$myID = (int)$_GET['id'];

$myAge = (int)$_GET['age'];