Telling the inlaws about unplanned pregnancy.?

Okay so here's the thing. I am 10 weeks pregnant and I have told my family mainly bc I need some support seeing as how it's my first pregnancy. My husband and I are planning on telling his parents and siblings on October 8th after my prenatal appt. The only thing is that the other day I had morbid sickness and was throwing up and she started talking about pregnancy. And at the time I thought it was a perfect time to tell her until she started freaking me out. She was saying stuff like she would be upset if I got pregnant and that she doesn't want grandkids and such. I'm sure she will be happy over time about it but now I'm afraid to tell her. And his dad is absolutely against the idea of us having a kid. They don't really care for me ad it is really making me afraid to tell them. Any advice??? Please!