In most states a child under 13 years old cannot legally ride in the front seat of a vehicle and must ride in the back seat of the vehicle.
The reason is because the airbag in the front of the vehicle can injure or kill the child so they must be in the back seat for their safety.
By law in most states a child that is under 13 year old is not supposed to sit in the front seat of a vehicle unless the vehicle is a single seat truck with no back seats.
If the truck has a back seat then the child is supposed to sit in the back seat until they turn 13 years old.
However as a kid I used to sit in the front seat of cars and vans and never got harmed but the reason kids under 13 are supposed to sit in the back seat is due to the air bag that can harm or kill the child.
The force of the airbag if it goes off can kill or severely injure someone under 13 years of age.
In some states you could get a ticket for having a 10 year old or any kid under 13 in the front seat.
So a old child could sit in the front seat and possibly get away with it but be aware that if a cop pulls you over and the child under 13 years old is sitting in the front seat and not the back seat then you could get a ticket and the under 13 year old would have to move to the back seat.