family and my baby

Let me just start this by saying I love my grandma. Shes great and been a large part of my life ever since I was born... she was very excited when we announced my pregnancy and has been overly opinionated on things from the start. She and my grandfather come over once a week to visit and I'm anxious every time. My grandma is a larger woman and dosent have a lot of feeling in one of her hands (she used to be a smoker and has had a stroke) I let her hold my baby girl and am usually sitting or standing right next to her to make sure everything is good. When she holds her, she tends to lean my baby kinda head down, butt up, so I have to readjust her alot. Last time she came over, I showed her how my baby likes to be cuddled in a chest to chest hold, and that would solve the whole, head down issue. I had her hold her that way, and it went well for a while but told her she still had to support her head. My baby bobbed her head a couple times and I reached over and helped her and she got offended, saying she had it. But she didnt. And this happened a couple times. My grandfather was also watching and caught my babys head once and he seen my worry and decided to just support her head for my grandma, which upset her because she said she had it. Me being momma bear, said "no you dont, you have to support her head, me and papa have both caught her head a few times now, here let me help you" and went to put her in the cradle hold for her but she got mad and said "just take her, nobody trusts me" so I let my grandpa hold her for a bit. Am I in the wrong? Any suggestions for what to do?