happy birthday under Christmas tree

Charlotte and I were walking home from barnehagen, and her little buddy next door was snowboarding (his dad pulling him along in the snow). He offered Charlotte a ride on his snowboard, and she sat on it and sled around, beaming. Then he said, wait! I have a present for Charlotte. A Christmas present. He made gifts for only two people in barnehage - his mamma and Charlotte. She said thank you, and his dad said wait til Christmas to open it. We took it inside and that night before bed she kept saying "happy birthday" or "where is happy birthday." Ahhh... now I get how that little mind works. Present = happy birthday. I said we ought to put it under the Christmas tree until Christmas Eve and she agreed and replied with "happy birthday under Christmas tree."