Mommy’s help plz

So I’ve done research of course every first mommy does they want everything to be done prefect for their Lo well I even have apps so my mil just can’t ever be wrong and keeps telling me it’s bad if I don’t warm up my daughters bottles that it will give her colic which I know it won’t but she says she knows because she has 5 kids I also never give my daughter formula unless she goes with someone if I’m around her I will literally feed her myself formula is expensive and yes we can afford it but why waste money if I can make milk myself so can you guys just reassure me because I know I’m right but she just keeps on 😑