Do you think it is too late to call others at 11 or 12 o'clock at night?

Yes, obviously it's too late to call someone at 11 or 12 o'clock at night because they have finished their busy day and gone to bed. If you call them, you disturb them. However, if you have an emergency, it is totally acceptable to call anyone at 11 or 12 o'clock at night.