No matter how old you are this is true.
thats why I take tylenol pm at like 7 and i'm asleep by 8
I stay up until at least midnight on the Eve. Most of the gifts are opened, and there is usually food involved, so getting to sleep is no problem.
Stay up until about 2 am, look at the spread that "Santa" emptied out of his sack, then go to sleep.
and then the next morning when you open that big heavy package hoping for like a tv or something and it turns out to be a big box of rocks because your family thinks it's funny to crush your soul