Volkswagen Golf GTI 2016, Owner'S Manual, Page: 398 / 1341

Keep your child in a booster seat until he or she is at least 4 ft. 9 in.
(57 inches / 1.45 meters) tall AND your child is:
tall enough to sit without slouching; and
able to keep his or her back against the vehicle seat; and
able to keep his or her knees naturally bent over the edge of the
vehicle seat; and
able to keep his or her feet flat on the floor; and
able to sit in that position during the entire trip.
The way the safety belt passes over the child’s body is important for
their safety and protection in a crash. Always make sure you child
can wear the safety belt properly:
The lap belt must lie snugly across the upper thighs, not the
stomach.
The shoulder belt must lie snugly across the shoulder and chest,
and never cross the neck or face.
Never let a child put the shoulder belt under the arm or behind the
back, because it could cause severe injuries in a crash.
Always check belt fit on the child in every vehicle. A booster seat
may be needed in some vehicles and not in others. If the seat belt