I replied in your old thread saying that a simple wrapper around the $_POST array doesn't really *do* anything. You shouldn't just put everything into objects for the hell of it, objects need to do something useful / provide some functionality.
The code you have posted, while wrapping a specific set of data sent via a POST request, doesn't give you any benefit, and in fact would need to be edited if ever you wanted your user to be able to submit there age for example. OOP is not about editing your objects every time you need to make a change.
I would be more inclined to develop a Request object. This Request object would wrap around *all* data contained within the users request. This is generally what most frameworks do and while it alone doesn't really provide any extra functionality or benefit, it does now mean that all your request data will be within one object instead of a series of arrays ($_POST, $_GET, $_REQUEST, $_SERVER etc etc).
However, I'm still not real sure what exactly your trying to do. As I said earlier, putting everything in classes does not necessarily mean its OOP and OOP is not simply jamming everything in classes for the fun of it.