@brightblossom We had to move up to 3-6m at 8wk too - LO was born 11lb 1oz.
He's currently 1wk away from 6m and a lot of his 6-9m stuff is starting to feel a bit snug on his 22lb body. He's long too, with big feet.
Glad I didn't buy too many items in bigger sizes early on - he has some summer...