you can use the number param to limit the number of pages you want and get the custom field in the foreach loop 🙂 (child of = your parent page, or the current page)
$mypages = get_pages( array( 'child_of' => $post->ID, 'sort_column' => 'post_date', 'sort_order' => 'desc', 'number' => 3, ) );
foreach( $mypages as $page ) {
$content = $page->post_content;
$content = apply_filters( 'the_content', $content );
?>
<h2><a href="https://wordpress.stackexchange.com/questions/61211/<?php echo get_page_link( $page->ID ); ?>"><?php echo $page->post_title; ?></a></h2>
<div class="entry"><?php echo $content; ?></div>
<?php
}