Removing Shortcodes from Child Theme

I’m trying to remove the shortcodes from a child theme.
In my functions.php file (for the child theme), I’ve put:

function my_remove_shortcode(){
    return '';
}
add_shortcode('entry-twitter-link', 'my_remove_shortcode');

Where entry-twitter-link is a shortcode created in the parent. However, the entry still shows up on my posts. Ideas on what’s wrong?

Try this out. Remove the already added shortcode then add the new shortcode on the init hook.

function shortcode_cleaner() {
    remove_shortcode( 'entry-twitter-link' ); // Not exactly required
    add_shortcode( 'entry-twitter-link', 'my_remove_shortcode' );
}
add_action( 'init', 'shortcode_cleaner' );

function my_remove_shortcode(){
    return '';
}