If you want to reorder product tabs, you can do this according to you wish as you want, just add the below code to your function.php.

<?php
add_filter( 'woocommerce_product_tabs', 'FindNerd_woo_reorder_tabs', 90 );
function FindNerd_woo_reorder_tabs( $woo_tabs ) { 
 $woo_tabs['reviews']['priority'] = 10; // Reviews first
 $woo_tabs['description']['priority'] = 15; // Description second
 $woo_tabs['additional_information']['priority'] = 20; // Additional information third 

 return $woo_tabs;
} ?>

In above code I have used filter hook (add_filter) to reorder product tabs contents.

Also here we have set first priority to review, second to description and third priority to additional information , but you can set priority according to your need.