I may have posted this before.
When our DDs came to us our elder DD was already in Juniors at school, so she had experienced a number of Christmases before both in birth family and in foster care.
We were chatting about our Christmas about 2 weeks before, and DD was upset to learn that in our house Santa brought stockings but not large presents (amazingly it hadn't crossed my mind that in other houses Santa brings big presents). We had to explain she got large presents in FC to make up for all the times with BPs when Santa hadn't known where to find her due to many moves .... 
So glad we didn't have to have that conversation on Christmas day...
So, if you have an older child for a first Christmas, please check what their expectations are so you can adjust accordingly!