Hi rebirth
You can open your present whenever you like - but its fun to wait till Christmas!! And yes its a good idea to post that you've received it cos that stops the sender from wondering whether it arrived
You don't have to say who sent it though. Hope this is helpful for you, enjoy!!
I'll be posting my gift later this week, my Santee hasn't said what they'd like so they'll a Yorkshire language book and a packet of Yorkshire pudding mix