Hi H.!!
My daughter is 6 and in california they have very strict car seat rules for children. She still has a car seat/booster seat. You may consider getting a seat that is more comfortable. My expereince with my daughter was that she is gonna fall asleep when I start driving anyway.. So in reference to your daughter read below. Hope this helps.
Rear-facing seats
All infants should ride rear-facing until they have reached at least 1 year of age and weigh at least 20 pounds. That means that if your baby reaches 20 pounds before her first birthday, she should remain rear-facing at least until she turns 1 year old. It is best for children to ride rear-facing to the highest weight or height allowed by the manufacturer.
There are 2 types of rear-facing seats: infant-only seats and convertible seats. Convertible seats can be used rear-facing for infants, and then turned forward-facing once your child is old enough and big enough to do so safely.
Infant-only seats
Infant-only car safety seat
Small and have carrying handles (sometimes come as part of a stroller system).
Have a built-in harness.
Are used for infants from birth up to 22 to 30 pounds, depending on model.
Many come with a base that can be left in the car. The seat clicks into and out of the base, so you don't have to install the base each time you use it.
Convertible seats (used rear-facing)
Are used rear-facing from birth until your child is at least 1 year of age and at least 20 pounds. It is best for children to ride rear-facing to the highest weight or height allowed by the manufacturer, usually 30 pounds or more for all new convertible seats. Check your car safety seat instructions to find the weight and height limits for rear-facing.
Have higher rear-facing weight limits than infant-only seats and are good for bigger babies.
Have the following 3 types of harnesses:
5-point harness—5 points of attachment: 2 at the shoulders, 2 at the hips, 1 at the crotch.
Overhead shield—A padded tray-like shield that swings down over the child.
T-shield—A padded t-shaped or triangle-shaped shield attached to the shoulder straps.
Features to look for in rear-facing seats
Harness slots. Look for a seat with more than one set of harness slots to give your baby room to grow. The harness should be in the slots at or below your baby's shoulders when your baby is rear-facing.
Adjustable buckles and shields. Many rear-facing seats have 2 or more buckle positions for growing babies. Many overhead shields can be adjusted as well.
Other helpful features. Angle indicators and built-in angle adjusters can help you get the proper recline. Head support systems can help your baby fit in the seat properly.
Forward-facing seat
Forward-facing seats
Once your child is at least 1 year of age and weighs at least 20 pounds, he can ride forward-facing. However, it is best for him to ride rear-facing until he reaches the highest weight or height allowed by the car safety seat. There are many types of seats that can be used forward-facing: convertible seats, built-in seats, combination forward-facing/booster seats, and travel vests.
Convertible seats (used forward-facing)
Convertible seats can be used forward-facing by children who are at least 1 year of age and weigh at least 20 pounds. To switch the seat from rear- to forward-facing, be sure to follow these steps:
Move the shoulder straps to the slots that are at or above your child's shoulders. On many convertible seats, the top harness slots must be used when the seat is in the forward-facing position. Check the instructions to be sure.
Move the seat from the reclined to the upright position if required by the manufacturer of the seat.
Make sure the seat belt runs through the forward-facing belt path.
When making these changes, always follow the car safety seat instructions.