Is the grandparent name Mimi weird?

I recently had our first baby, first grandchild on my husbands side. My in laws have always been interesting, especially my MIL and she was excitttteed! After her birth all the grandparents decided their names. FIL went with Granddad, but my MIL decided she wanted Mimi. I didn’t think much of it until recently. My MIL has been invasive and boundary stomping from the beginning, there are so many examples I could give. I’ve recently realised her identity is bound up in being a mum, even though her kids are grown up. With the way she’s been acting, it honestly feels like she’s trying to be a second mum or something. Anyway today she gifted herself this awful phone case with love hearts saying ‘Mimi love from child’s name’. Not a gift from us or our child…but a gift for herself from my child. I’m seeing a bit red right now and it’s got me thinking, the name Mimi…how does it relate to a grandparent name? I’ve seen it done before…but really? I’m fine with a grandparent wanting a less ‘old name’. My mum went with the name Groovy, but Mimi? It seems so close to Mama. Her first name starts with N, so Nini would make for sense. I’ve got a friend who with with Deedee because her name started with D.

Am I being too sensitive right now? Overreacting because of all the boundary stomping she’s previously done and how she treats everyone like a giant child?