When to move to the next type of teat?

[SalmonLadder]

I've started to notice that when feeding, the teat of the bottle is sometimes getting sucked inwards. Does this mean that my dd is ready to love up to the next teat as the milk isn't coming out quickly enough? She's a couple of weeks away from the ages guidelines that they give for the next size but I think she is sucking too quickly for the size of test we are using. Thanks!

I'd def move up a teat now - what's written on the packet is just a guideline. I know some people who have had to put a newborn on the 3m+ teats because they were so greedy!