[LittleLifeSize]

It really is a maturity and slouch thing. Getting my almost 6 year old nephew into a 5pt carseat is a struggle because he slouches just sitting there before I buckle him in, so I think your decision has to be your own, and you have to trust that she stays properly buckled and doesn't move around. I think over the age of 5, its a personal decision between the parents and their trust in their child.