Data belum dikirim.<br><br><form method="post" action="index.php">
    Nama: <input type="text" name="nama" required><br><br>
    Umur: <input type="number" name="umur" min="1" required><br><br>
    Kelas: <input type="text" name="kelas" required><br><br>
    <input type="submit" value="Kirim">
</form>