Am I being overly sensitive? 😢

Okay so I'll try to keep this short. 
So my brother and his wife are having a baby in a few weeks. This is their  second and they are having a boy. They decided on naming their son after our dad who passed away almost ten years ago.  My SIL went to a doctors appointment recently and they moved her due date to September 3rd, which is the anniversary of my dads death. Ten years.
Now I obviously know she had no control over when she has the baby. But she will not stop talking about how she really hopes she has the baby on the 3rd. All the time. Today's she posted a status on Facebook about how she really thinks the baby will be born on the 3rd and how it will make that day such a happy day for my brother and his family. Blah blah blah. But no matter what happens that day it will always be the anniversary of the worst day in my life.   That's the day I felt my dads heart beat for the last time.  I just feel like she is being insensitive about the whole thing. I'm not going to be mad at her if he is born that day.  But I just wish she would stop talking about it.  
So now all her family are saying things like " oh he has his name and he will be born that day!" And it is just getting me upset.  I know I'm probably being stupid about it all.Â