I am writing $(this).closest(\'.comment\').find(\'form\').toggle(\'slow\');  and the problem is each of the forms in the child is being toggled. I would like on         
        
The simplest way to get the first result of find is with good old [index] operator:
$('.comment').find('form')[0];
Works like a charm!
You can use either
$(this).closest('.comment').find('form').eq(0).toggle('slow');
or
$(this).closest('.comment').find('form:first').toggle('slow');
                                                                        Use the below example for jquery find to get the first element
More filtring methods With Demo
$(document).ready(function(){
  $(".first").first().css("background-color", "green");
});
.first{
    padding: 15px;
    border: 12px solid #23384E;
    background: #28BAA2;
    margin-top: 10px;
}
<!DOCTYPE html>
<html>
<head>
<title>jQuery First Method Example By Tutsmake</title> 
<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script> 
</head>
<body>
 
<h1>This is first() method example</h1>
 
<div class="first">
  <p>A paragraph in a div.</p>
  <p>Another paragraph in a div.</p>
</div>
<br>
 
<div class="first">
  <p>A paragraph in another div.</p>
  <p>Another paragraph in another div.</p>
</div>
<br>
 
<div class="first">
  <p>A paragraph in another div.</p>
  <p>Another paragraph in another div.</p>
</div>
 
</body>
</html>
I use
$([selector]).slice(0, 1)
because it's the most explicit way to select a slice of a query and because it can be easily modified to match not the first element but the next, etc.
Use :first selector like below :
$(this).closest('.comment').find('form:first').toggle('slow');
                                                                        using jquery simply use:
    $( "form" ).first().toggle('slow');