My DD is nearly 3 months old. I have been bottle feeding her with Tommee Tippee bottles and stage 1, slow flow teats. I know stage 1 teats are recommended for 0-3 months but my DD still seems to get on fine with them. Is it best to change over to stage 2 at 3 months? Also there seems to be different varieties of stage 2 teats, how do I know which ones to go for? Any advice gratefully received.