I'd planned (but not booked) a big birthday party for my child this year on the actual day (never had one before), mentioned this to a friend and she wants to make it a joint one with her child (almost same age). They have a lot of friends in common, so in a way it makes sense, but I had really wanted it to be a special party, and I feel sharing it just won't be the same. They get on ok (our kids), but they can be quite competitive with each other. I'm just not sure.