cookie create with php and ajax can't be read in wordpress

i create a simple cookie with ajax method post, by a popup with a button, this button calls the ajax function.

the cookie is there, exists, but i can't read it inside wordpress by a shortcode or a function.

Ajax function

<script>
function cookieC(){
        var v1="datacookie";
        var param = {
                "v1" : v1
        };
        $.ajax({
                data:  param,
                url:   'cookie_create.php',
                type:  'post',
                beforeSend: function () {
                                        },
                success:  function (response) {
                       alert('ok');
                }
        });
}
</script>

PHP cookie_create.php

$data = $_POST['v1'];
setcookie( 'namecookie', $data, time() + 3600);

Inside wordpress i try read it

Function.php or in the main file of a plugin.

if(isset($_COOKIE['namecookie']))
{
  echo "All right";
}
else
{
echo "something is wrong"; 
}

no matter what I do, always prints else

via Chebli Mohamed