Can’t get jQuery to enqueue into post edit script

Use the admin_enqueue_scripts hook to add your own custom script. Put it in an external file, and use wp_localize_script to pass any data from php to javascript. jQuery is already used on the admin side, adding a script tag sourcing it from google will break things.

function wpa80418_admin_enqueue( $hook ) {
    if( 'post.php' != $hook )
        return;
    wp_enqueue_script(
        'my_custom_script',
        get_template_directory_uri() . '/js/myscript.js',
        array('jquery')
    );
}
add_action( 'admin_enqueue_scripts', 'wpa80418_admin_enqueue' );