My baby was also taking around 120ml at 4 months, and my paediatrician said every baby is different. What's more important is the total milk intake over 24 hours, the number of wet diapers, and whether baby is active and meeting milestones. If your baby's weight hasn't increased at all for a while, it would be a good idea to consult your paediatrician to rule out any feeding or growth concerns
Don't worry ya. My baby still drink 125ml when she was 1 year old. Now she is 16 months and drink around 160ml and weigh around 9kg. As long the output is good, it's fine
A four-month baby should be around 7.0 kg if the baby is a boy and 6.4 kg if the baby is a girl. check whether your baby has age-appropriate weight,