DD will be 2 when new baby is born and we currently have her in her car seat which we want to use for new baby and get DD a new booster. Thing is, she is 14 kilos now and thus fits the 14-26kg range for a booster but I still think she is too young for one even though the weight is correct. I would prefer the convertible booster seats which go from 8-26 kilo but DH argues that as long as she is 14 kg then she doesn't need the convertible one. Any ideas?