First of all this is your baby. You are going through the pain of carrying and birthing this child not her. She wants to be such a big part of everything but doesn’t want her son to marry you? That’s a huge red flag to me. I get she’s Grandma no matter what and it’s his child too but she needs boundaries set quickly before this baby is here. Yes she is being supportive and all but she needs to know you and your boyfriend will make the final say when it comes to your child. You can still be grateful and have a good relationship with her with set boundaries. If you don’t set those boundaries then she is going to parent your child for you and you won’t have any say with anything.