Who gave birth to her, Me or You?

Ok, I have no problem with parenting advice but when others say Do it this way" That is telling me and not advising me. I am always open to advice of any kind, including parenting advice. Being a new mom has it's challenges, and I am grateful for the advice but sometimes it gets overwhelming with advice. I recently read up in one of my many baby magazines that it is better to stir the bottle instead of shake it,causes less bubbles for gas. So I came up up something even more creative. Since I don't always want to stir I take the bottle inbetween my palms rub together. This creates a stirring type action. Well my mom's partner saw me doing this and asked what I was doing and then I explained. Well as the week goes by I am told "oh don't do that do this". I was told to loosen the nipple base and squeeze the bottle to reduce the air, this would have to be done about three times. I find this to be ineffective and time consuming. She likes things done there way anyway. Well this morning my child was brought to me and I was told to take her and change her or something. Well my brother was there and asked me if I wanted him to take her, I said ok just change her diaper and bring her back(so I could breastfeed). So then she asks me why didn't I take her, I said I had a headache(didn't want to sit up right away,sleep headache). So I am like, 1)Why are you asking me why I didn't do something,and 2)Who are you to be saying anything to me about it, you are not my mother. So I am sitting here wondering why in the hell does she feel the need to always have an input about how I handle my child. Like I said, advice is one thing but telling me it has to be done this way is another. I honestly don't know how to approach her on this because she is hotheaded and controlling. But I am not going to just sit there and take this from her forever.