Tidak bisa pindah dari file proses daftar otomatis masuk ke form login?

prosesdaftar.php

<?php
   include("koneksi.php");

   $msg="";
   if(isset($_POST["daftar"])){
		$id_user 	= $_POST["id_user"];
		$nama 		= $_POST["nama"];
		$username	= $_POST["username"];
		$password 	= $_POST["password"];
		$level		= $_POST["level"];

		$id_user	= mysqli_real_escape_string($conn, $id_user);
		$name 		= mysqli_real_escape_string($conn, $name);
		$username	= mysqli_real_escape_string($conn, $username);
		$password	= mysqli_real_escape_string($conn, $password);
		$level		= mysqli_real_escape_string($conn, $level);


		$sql="SELECT username FROM user WHERE username='$username'";
		$result=mysqli_query($conn,$sql);
		$row=mysqli_fetch_array($result,MYSQLI_ASSOC);
		if(mysqli_num_rows($result) == 1)
		{
			$msg = "Sorry...This email already exist...";
			header("location:daftar.php");
		}
		else
		{
			$query = mysqli_query($conn, "INSERT INTO user (id_user, nama, username, password, level)
			VALUES ('$id_user', '$nama', '$username', '$password', '$level')");
			if($query)
			{
				$msg = "Thank You! you are now registered.";
				header("location:login.php");
			}
		}
	}
?>

saya ingin membuatnya agar otomatis ke form login tapi kenapa stuk di prosesdaftar.php ?