Boundaries

I lost my mom about 5 years ago. This is my first pregnancy and it’s been hard for me not having my mom through it all. I am trying to keep all my in laws up to date and involved as much as possible, just like i am with my own family. But my husbands mom is trying to act like she’s my actual mom. I have told her before i don’t feel comfortable with her my mom. She’s my mother in law. The only other woman i call mom is my step mom, but she’s been fantastic to me since she came into our lives, my mother in law hasn’t. She’s disliked me from day one and i feel the only reason she’s being nicer is because I’m pregnant. I want her to be involved in her future grandchild’s life, but I’m tired of her over stepping boundaries, like posting pictures of my ultrasounds and my baby updates on social media when i don’t even do that. I have already talked to her about it but she doesn’t seem to listen. Any advice?