When my son was just about 4 months old my son was already drinking 8oz every 4 hours, his dr told us to start rice cereal but I didn't till 5 months. All babies are different.
I know alot of people give their baby this much and are fine. My son is 7 months old and since he was 3 months he's been drinking 4oz of milk every 2-4 hours except at night. (he sleeps through the night)