my lo never opened her mouth really wide hun they just have small mouths if you cant see much of the bottom brown bit its ok. she still does now she open wider when the let down goes, they tried to say to me she was lacthed right, but then i did it there way and forced her to open as wide as she could then she started getting fussy and not putting on much weight. just work with it and let baby lead you for a bit see if you have any change. i believe they have to be comfortable as well to feed. my lo is 4 months xx