Neither of my girls were or still aren't big "drinkers". Dd2 didn't have the same problems yours does as far as the problems with gerd, she just had mild reflux but, what kind of formula does she drink? Rice based ones like Similac Sensitive in the lime green lids were fantastic for dd2... Also, how about a soppy cup? Both my girls let bottles go at 10 months. I got the Nuby cups to start with, it doest require a bite flow and it was easier for her to get more at a time. Her weight sounds fantastic. As patents we worry about our kids being hungry but luckily they still have very primitive human brain functions and they will not let themselves go hungry. Ask your pedi about adding rice cereal to her bottles for extra nutrients ad iron although my kids preferred the oatmeal. Just keep an eye on her urine output and color and odor.. If it gets dark or strong like a sign of dehydration call dr immediately if she's not losing weight I'd say she's just perfect! Neither of my girls took the standard 24 ounces per day, they both drank in the 18-20 oz range, and at 7 months with table and solids going they are getting more nutrients from foods also. Good luck and let us know!
All the things I dreamed you'd be are all the things you are. You will always be my little girl, always my shining star." 1 Samuel 1:27