仅为真实访客在Age Gate上设置Cookie

Question

I'm building an adult toy store in OpenCart and the wholesale company requires an age gate, which I've built using a simple cookie script in the header file:

if (!isset($_COOKIE['agecheck'])):
    $this->redirect ($this->url->link('common/agegate'));
endif;

This works great when the visitor is a live person, but when trying to use social sharing buttons the cookie is blocking Facebook, Google+, LinkedIn from accessing the correct product page.

Does anyone know of a solution for this? A solution using jQuery would also be acceptable.