How do you deal with a child that is already begging to open presents..its only 10am?!?

We open presents Christmas Eve, so the anticipation has been building...she doesn't seem to understand the difference between today and tonight...we had a little chat about it but I want to be prepared if she asks again. I don't want to be Scrooge and threaten to take away presents because I need to follow through with my discipline and I won't do that! :)