How much expressed breastmilk does a 3 month old usually consume per feeding? Mine has been taking 100ml per feeding since 2 months old. Wondering if that's okay.

There is no real /long established formulae or baby to drink as most of the recommendation are based on fm volume. On top of that, everybody's bm is slightly different, some are more fattty or protein so baby will want to drink more or less of it. Some baby also big drinker, some are small drinkers. As long as baby drink to his fill, does not vomit /regurgitate too much, u guys never force feed then it is ok. If hungry they will cry for milk. U can slowly try to increase or decrease base on how many hours baby is always asking for milk. Sometimes growth spurts or teething can causes increase or decrease of milk intake. So long baby is active, and gaining weight well, got pee got s***, then all is good