My term baby was about that weight at 12 weeks... So I wouldn't worry too much. If she's gaining weight as expected and following her line, I wouldn't worry! I breastfeed so don't know about volumes I'm afraid!
My baby is 12 weeks (9 weeks premature) he is having 3oz sometimes less every 3 hrs as long as they have plenty of wet and dirty nappies and are putting on weight it will be fine If they drain the bottle every time make them up to 5oz they will only ever drink what they want/need xx
my 17 week old also only has 4oz at a time with lots of encouragement. out of the all the bottles she has she almost always leaves a little bit at the end. just had her 4 month health review and the health advisor was very pleased with her weight gain and how much she’s growing. baby was born 40+3 the only 2 bottles that she finished and we offer more for is one of her night feeds and then her morning feed