Talking down to kids

My fiancé grandma love to tell me that my child is not advanced. My baby is 3 months and she tells me oh baby should be sitting on her own, baby should be rolling over without assistance. It’s just upsetting because I believe my baby is doing good and hitting all milestones. But she continues to be so negative and she has only seen my baby twice since I don’t really let ppl around her with COVID and all. I’m really about just tell her she can’t see baby anymore until she fix her attitude.