WP_Error on attribute + term insert

I want to add a product attribute (wc_create_attribute) & assigned terms (wp_insert_term) via the functions.php.

Example:

$args = array(
  'name'         => "Color",
  'slug'         => "color",
  'order_by'     => "menu_order",
  'has_archives' => "",
);
wc_create_attribute($args);

$add = wp_insert_term( "Blue", 'pa_color', array( 'slug' => "blue" ) );
print_r($add);

The wc_create_attribute() works fine, but when the wp_insert_term() runs it throws an error because of “Invalid taxonomy”.
When I then reload the page, it works fine because then the taxonomy is not invalid anymore.
So it seems that the wp_insert_term() are executed before the create_attribute somehow. I don’t understand why it does not work in one attempt.

Maybe you can help me