Baby names

So, me and my partner have already kind of agreed on baby names, we have both a girl and boy name. The girl name, is one I’ve had picked out since I was 13 and my partner is happy for us to use it as he likes it as well. Now the boy name, took us a lot longer to agree on but we finally came to a name choice that we both like. My partners mum (my future mother in law) asked us if we had any name options, so we told her our options and to both, she said “I don’t like that name” or “so and so’s child has that name”. Now I’m not bothered by her opinion and neither is my partner, he even agreed with me that it’s not up to her and wether she likes the names or not, doesn’t matter but my problem is, how do I deal with her saying she doesn’t like the names we have chosen, especially when we actually use the name for our child. It is frustrating to me and even to my partner as it is our child and we like the names and we don’t really want to listen to her opinions. I generally get on very well with my MIL but this one thing really irritated me