About rewriting the rules... you can use these lines of code (tested and working). Don't know about the redirection thing you mention though.
add_filter('rewrite_rules_array', '_rewrite_rules_array');
function _rewrite_rules_array($rewrite_rules) {
$taxonomy = "age-limit";
$taxonomy_slug = "age-limit";
$month_rule = array($taxonomy_slug .'/(.+?)/([0-9]{4})/([0-9]{1,2})/?$' => 'index.php?' . $taxonomy . '=$matches[1]&year=$matches[2]&monthnum=$matches[3]');
$year_rule = array($taxonomy_slug . '/(.+?)/([0-9]{4})/?$' => 'index.php?' . $taxonomy . '=$matches[1]&year=$matches[2]');
$rewrite_rules = $year_rule + $month_rule + $rewrite_rules;
return $rewrite_rules;
}
This WordPress plugin helped me understand rewrite rules a little better: Rewrite Rules Inspector