checking users html form info with PHP on same page

I am trying to write a simple html form which requires the user to enter the correct email and password, using $_SERVER as the action for my form. I do not want to send the POST info to another php page, but I want to do it on the same page instead.

I have set two variables, $correct_email and $correct_password.

Here is the form;

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>">
        <label for="eml">Email:</label>
        <input type="email" name="eml" id="eml" required>
        <br>
        <label for="pwd">Password:</label>
        <input type="password" name="pwd" id="pwd" required>
        <br>
        <input type="hidden" name="checkMe" value="12345">
        <input type="submit" name="submit" value="Submit">
    </form>

Here is what I am trying to get work in PHP

$correct_email = "(my personal email)";
$correct_password = "password"]; 

if ($_POST['eml']) == $correct_email && ($_POST['pwd']) == $correct_password {

    echo "<h1>You are logged in</h1>";



} else {

    echo "<h1>error</h1>";


}

It is not working, please help! I am also unclear on whether the PHP should come before or after the form.

Also, I would like to have the form be cleared from view, on the page, when the correct info is entered.

Thanks so much