In cartoons, kids are portrayed as being way shorter than adults, even kids who are seven to twelve years in age. In real life, seven year olds are on average four feet tall, but in cartoons, seven to eleven year olds are often drawn to be only half adult height. Despite that children are rather small when they're young, it doesn't stay this way for long in real life (unless that is, they have a growth condition but that's another story entirely), especially when puberty sets in and they outgrow clothes faster than they get new ones. In some cartoons however, it's much more exaggerated. Even ten and eleven year olds only appear two feet tall.