Show post number (Not Total Number of Posts)

I want to show the post number of the post (not total number of posts)?

For example –
for 5ths post – should display post no. 5.

I am trying following methods : (https://www.ads-software.com/support/topic/show-post-number).

Problem – But 1st post is repeating two times in each page.
URL – https://www.makemoneyfreemoney.com/

I did following things :

a) In function.php
function Get_Post_Number($postID){
$temp_query = $wp_query;
$postNumberQuery = new WP_Query(‘orderby=date&order=ASC&posts_per_page=-1’);
$counter = 1;
$postCount = 0;
if($postNumberQuery->have_posts()) :
while ($postNumberQuery->have_posts()) : $postNumberQuery->the_post();
if ($postID == get_the_ID()){
$postCount = $counter;
} else {
$counter++;
}
endwhile; endif;
wp_reset_query();
$wp_query = $temp_query;
return $postCount;
}

b) In default.php (index.php)
$currentID = get_the_ID();
$currentNumber = Get_Post_Number($currentID); ?>
<?php echo $currentNumber; ?>

So, please give me proper suggestion for fix the issue.