She needs to accept that you don't want her there.. it's childish of her to not respect your wishes and play that card
I just know the more ppl there is going to make more nervous. I just want to be relax and experience this moment with my boyfriend and mom. My mom is there Because she's my backbone and it's always just been me and her all our lives I would feel empty without her there but if she wasn't I will still be ok. I just want a intimate private delivery
I think she's got to understand that you may be different than her and respect what you want. Just talk to her again about how special she is to you and explain why you don't want her there at that time and how it's not anything against her, or first talk with her and find out why she's so upset but stick to your guns, maybe give her a special task to do like help you pack your bag or something, I'm so tired right now I hope this thought helps! Good luck!