We have a 0+ car seat that says it is 0-13kg and up to 12-15months. Looking at typical weights of children, my DD won't be 13kg until she is about 2 (currently 8 months). Do I need to buy a new seat soon or can I stick with this one? Or is she likely to get too tall whilst the weight is fine? We are looking to buy a new car in about 6 months so don't really want to buy a car seat before the car and trying to work out how long the seat will last us.