In laws

I am 29 and have been with my SO for 9 years. Living together for 8. This is both of our first baby, it was planned. We have our own house. Anyways told my parents we were expecting and they were super happy and supportive. Told his mom and got an are you serious? I would have told you not to do that but it's too late. I'm annoyed by her reaction anyone have a similar situation or advice.