Ok ladies I need your advice

So I am really worried about my sister in law finding out my hubby and I are having a baby. In August 2014 she gave birth to her son at 24.5 weeks, but sadly in October he passed away. She is still having a hard time with him being gone. I'm not sure if she would be happy or mad at us for having a baby and it's really worrying me. I know I shouldn't worry, but this is our first pregnancy and I'm already scared. In hoping for a happy and healthy 9 months, but I'm nervous.