Depth parameter not working; like to display children and *not* grandchildren

I’m trying to display the children of a post and not the grandchildren of the post. I’ve been trying to set the depth parameter, but for the life of me, I can’t get it to work. What am I missing?

<?

global $post;

$ancestors = get_post_ancestors( $post->ID);

$ancestor = $ancestors[0];

$children_args = array(
	"child_of" => $ancestor,
	'sort_column' => 'menu_order',
	'depth'        => 1
);

$children = get_pages($children_args);

?>

<ul class="ancestor_menu">
							<?php

							foreach ( $children as $child ):

								global $wp_query;

								$postID = $wp_query->post->ID;

								if($postID === $child->ID) {

									$active = ' class="current-menu-item"';

								};

							?>
								<li<?=$active?>><a href="<?php echo $child->guid; ?>"><?php echo $child->post_title; ?></a></li>
							<?php

							unset($active);

							endforeach;

							?>
							</ul>