Do any token extensions provide a token for "age" rather than just DOB?
I don't see any either, but the code to use in such an extension (as either a token or even a smarty modifier) seems pretty straightforward:

https://github.com/civicrm/civicrm-core/blob/5.19.2/CRM/Contact/BAO/Contact.php#L2677-L2684

      if ($contact-&gt;birth_date) {
        $birthDate = CRM_Utils_Date::customFormat($contact-&gt;birth_date, '%Y%m%d');
        if ($birthDate &lt; date('Ymd')) {
          $age = CRM_Utils_Date::calculateAge($birthDate);
          $values['age']['y'] = CRM_Utils_Array::value('years', $age);
          $values['age']['m'] = CRM_Utils_Array::value('months', $age);
        }
      }