Depends if they are taking the bottle just fine on test 0. Mine was taking like 45 mins to finish a bottle and getting bored I changed her to size 2 like 2 weeks ago when she was 7 weeks old and she does much better on them
We are using 1s at 10 weeks, she sounds like she is drowning with a 2. They say to size up if it takes longer than 15 minutes to finish a bottle or if they get frustrated, bored or fall asleep when feeding.
We’re on size 2 and have been for a couple of weeks, currently 10 weeks old. She’s getting fussy on them now, so considering trying a size 3
Went up to size 1 at 5 weeks and size 2 at nine weeks.
My 12 week old is still on size 0, I tried 1 a few weeks ago and he just choked and spluttered everywhere! If baby is falling asleep at bottle or fussing and taking forever to drink it that’s the normal sign to move up a size!