I’m currently using size 1 teat that the newborn bottles come with, but I’ve been noticing over the last week or so that when I’m feeding my daughter the teats are sucking in (not sure how to explain it) she’s 12 weeks old. I’ve looked online but can only find size 1 or size 3 teats which are for 6 months plus.. do I continue with the teats I have or do I move onto the next size ?