SOs parents over stepping boundaries

Chelsea
This is a very long post, Sorry! But I really just need to get it off my chest and maybe get some advice. So I feel like my SOs parents kind of over step their boundaries sometimes, or maybe don't realize when things they do are inappropriate. For example, most recently my SOs mother told us that she thinks we should name our daughter after her and my mother, she has brought this up twice. which I feel is kind of inappropriate, you shouldn't ask someone to name their child after you, whether your the grandparent or not. But that's not a huge deal, we told her no and that is hopefully going to be the end of it(although she might keep pushing it). Then we had a baby shower, so she thought she'd make a Facebook event page, which is completely fine! I was all about having her be apart of the process! I told her it was an all girl party, and that we could only have a limited amount of people at the venue, but told her it would be alright for her to invite A FEW people. she invited 21 people on the page, and I only knew 4 of them, 7 of the people she invited were guys. I had my SO tell her that it wasn't ok, so she deleted the page and only invited 5 people it was resolved quickly, but still very annoying. Im also nervous that she is going to try to be in the room while I'm in labor, which I'm not comfortable with. I have social anxiety, and don't think I'll be able to handle her in there. My SOs brother has had 2 kids, and their mom makes a pretty big deal out of the fact that they didn't let her in the room while she was in labor, I've heard about it a lot. I don't want to have to deal with her throwing a fit about not being able to be in there, it's not fair to me. But the biggest thing is that since we first found out we were having a baby, SOs parents have been railing us to get married, which is a huge annoyance to me. We are only barley 20, there were no plans to get married before the baby, I feel like that shouldn't change right now, we aren't ready for that yet. They are constantly asking when it's going to happen, and I can't stand it. My SOs brother and his girlfriend have 2 kids, and for a while she cut his mom off, stopped talking to her, stopped letting her see the children, blocked her on Facebook, and I'm not 100% sure why it happened, but i know it really upset their mom. I'm very nervous that it was because she constantly over stepped her boundaries, and that it's something I'm going to have to deal with very soon. Any advice? How can I tell her she can't be in the delivery room? How can I explain that we aren't going to get married for a while? How can I keep the peace while kindly asking her to back off?