Actually, now I look back at your form and email code I can see why you aren't getting any content - you are using variables in the body of your message but not defining them or allocating values (the variable names above where you assign the posted data are different). You code can also be simplified a lot:
<?php
/* Subject and Email Variables */
$emailSubject = 'Insomnia All Ages Promoters';
$webMaster = 'aaron@superbsoundentertainment.com';
/* Gathering Data Variables */
$name = $_POST['name'];
$email = $_POST['email'];
$mobile = $_POST['mobile'];
$school = $_POST['school'];
$dob = $_POST['dob'];
$address = $_POST['address'];
$why = $_POST['why'];
$body = '<br><hr><br>';
$body .= 'Name: {$name}<br>';
$body .= 'Email: {$email}<br>';
$body .= 'Mobile: {$mobile}<br>';
$body .= 'School: {$school}<br>';
$body .= 'DOB: {$dob}<br>';
$body .= 'Address: {$address}<br>';
$body .= 'Why: {$why}<br>';
$headers = "From: $email\r\n";
$headers .= "Content-type: text/html\r\n";
$success = mail($webMaster, $emailSubject, $body, $headers);
I am not sure if the form action (contactformprocess.php) is sending to a new page or the same page but if you want the success message to appear on the same page then the code above needs to be at the top of the page with your form and then underneath the Submit button on the form you would put:
<?php if ($success) { ?>
<div>
<div align="left">Thank you for signing up! We will be in contact with you very soon! Kind regards the team at Superb Sound Entertainment</div>
</div>
<?php } ?>