Controlling MIL?

My MIL irks my nerves! She has no right to tell my husband to tell me how to announce my pregnancy . He told her we are expecting. I didn't tell her because he really wanted to do it so I let him . She's been acting like she doesn't know which I find annoying because I know she knows . She then texted my husband to tell him not to tell me she knows . And then had the nerve to say and make sure she doesn't post sonograms online !!!! I've told my concerns to my husband and he sees nothing wrong !! She can barely raise her 5 kids never mind try to control me on how I'm gonna announce mine . This lady is out of control and I'm about to lock her ghetto controlling ass into place! Input please ladies!!