Unneeded baby advice

My baby is 9 days old today and my boyfriends mom has mentioned to me 2/3x in the last couple days that if I'm wanting to really get the baby to sleep at night and put her on a schedule that I need to put a teaspoon of rice in her bottle, that's what she did with my bf when he was a baby. Well this is not news to me it seems like a lot of the older generation did this. And when I had my son people told me the same thing, and I did that for him but at like 4/5 months old not days old. She had mentioned earlier while holding the baby that whenever she went to the store that she'd get some rice to put in her bottle, and I politely brushed the statement off. His mom can be very pushy if not in agreement with her, and I'm wondering how do I tell her I'm not comfortable with giving the baby rice because I feel that she's too little. I already said to her that yes I did that before with my son but I waited until he was 4 or 5 months before I gave that to him, thinking she's get the point that I'm going to wait with this baby as well. I know for some people they are easily able to just say no I don't want to do that but I have such high anxiety already and just with how pushy she can be I just don't want to hear here tell me how well she did it and nothing happened to her baby as a child and all that mess. I just want people to respect my parenting and my choices.