I found it curious that she was willing to give up Christmas eve/day so easily. We made it a point every year to be both awake to see the kids run to open their gifts, and it's easy for her to *not* do that this year?!?!
Did she offer to give up Christmas or Christmas Eve? The person who gets Christmas Eve is typically the one who gets to do the night-before traditions and see the kids wake up and run to open their gifts.
Just pointing out nuances so you don't get hoodwinked.