^^

if you can wipe it off it's just milk residue, if you can't, it may be thrush.

my daughter started off with white coating on her mouth which her pediatrician said was normal but weeks later i noticed the coating turn from white to blue and come to find out it was thrush

Sounds like thrush...the roof of her mouth is white which according to her pediatrician is normal but her tongue is pink

Careful it may be thrush