function htdat_shortcode_atts_products( $out, $pairs, $atts, $shortcode ) {
    if ( isset ( $atts[ 'is_new' ] ) && $atts [ 'is_new' ] ) {
        $out[ 'is_new' ] = true;
    } else {
        $out[ 'is_new' ] = false;
    }

    return $out;
}
add_filter('shortcode_atts_products', 'htdat_shortcode_atts_products', 10, 4);

function htdat_woocommerce_shortcode_products_query( $query_args, $attributes ) {
    if ( $attributes[ 'is_new' ] ) {
        $today = getdate();
        $days_ago = 30;
        $query_args[ 'date_query' ] = array ('after' => date( 'Y-m-d', strtotime( '-' . $days_ago . ' days', strtotime( $today['year'] . '-' . $today['mon'] . '-' . $today['mday'] ) ) ),);
    }

    return $query_args;
}
add_filter( 'woocommerce_shortcode_products_query', 'htdat_woocommerce_shortcode_products_query', 10, 2 );