C.J.
This is coming from someone who has a sister that has a birthday the day after mine and another sister that has a birthday exactly a month later. I have always had a combined party and my other sister shared her birthday with my grandpa until he passed away.
I really would have liked to have had a birthday just for me be that never happened. I always felt that I was "punished" for when I was born and to top it off, it was after Christmas.
I small "half" birthday is a cute idea and I do that for my son because his birthday always falls near Easter.