Ordering posts by custom fields

This is a code I’m using ina website that I’m creating for a client. Maybe it can point you in the right direction:

$current_date = date('Y-m-d');
$args = array(  
    'post_type' => 'billboard_evento',
    'posts_per_page' => 4,                            
    'meta_key' => 'fecha-inicio', //Declaring wich meta key I want to use
    'orderby' => 'fecha-inicio', //Ordering the queried elements by meta value 
    'order'  => 'ASC',

    'meta_query' => array(  //Querying by meta field
        array(
            'key' => 'fecha-inicio', //meta field name for an event start date
            'value' => $current_date, // Setting the value to current date
            'compare' => '>=', // Comparing current date with event start date
            'type' => 'DATE', //Type of value
        ),
    )
); 
$query_eventos = new WP_query($args);