Mom trying to take my place

I had twin girls 4 months ago and my mom (their grandma) has become way too involved I think. She wants to be here with them every single day and if she's not here she's constantly texting me saying she misses them and how she should be here with them.

Last month I mentioned they are getting to that age where I think they're going to start picking a favorite parent, and she said that she really hopes it's her. If I text her that they're being very fussy one day, she says its probably cause they miss her and need her here.

I take pictures every month they get older and she makes it a huge deal and wants to be here for every one. She wants to be there for every single first for them, zoo trip, aquarium, park, you name it she wants to be there.

I worry with her being here so often that maybe they will pick her as a favorite and I wont be able to soothe them. Although she is only here 2 or 3 days out of the week for 3-6 hours, I still get nervous they might favor her over me.

I am a stay at home mom, my husband is home from work by 1 or 2 and is a very hands on father.

Dont get me wrong having the help, especially when they were younger is great. Now they're teething and it is so nice for me to get a break sometimes. But honestly i'm reaching a point where I dont want her around and I dont want the help because it feels like she is trying to take my place as mom.

She is the type of person who if I go to her about my feelings, her first response is "oh sorry im so terrible and I ruin everything" and her second response is to simply ignore me.

I dont know if i'm looking for advice, just to rant, or to find someone who just understands. But its a lot, it makes me sad, it makes me mad, and i dont know what to do.

**Edited to add : I have set boundaries with her already and have communicated that my time alone with the girls and as a new family of 4 is very important to me. She was coming over every day and spending the whole day here. I have told her she can now only come over 2 days so that I can go to the gym or run errands. She still complains about it and texts me every single day saying she feels wrong that she isnt here and that she should be here, I dont always answer but if I do I simply say she has her own life, and job that she needs to focus on.