my baby just turned 5 months old. he born premature 1 month and drink 60-115 ml every 3-4 hours and only 6-7 hours when sleep at night. but never refuses milk. I always wait him hungry only give him drink . you need check baby growth chart (weight, height) to see whether develop as per normal rate. probably need to change type of milk maybe not suitable for baby.
do continue to follow your baby's hunger cues and contact PD or polyclinic to ensure she getting enough to eat, especially if she not gaining weight well