I guess it would depend on how she sleeps with her arms free? If she still depends on the wrap for sleep, I'd get the next size up but maybe start transitioning her as well (it can take time for them to get used to). I've had to buy a few new gro-bags because Alex has grown out of the 0-6 month size - he's too long and his feet are right at the bottom! Makes me rather glad we got the car seat we did though, a friend of mine had to buy a new seat because her DD cracked 9kg but was nowhere near ready to be forward faced