Bridge to Terabithia is very much a work of children's literature. The language Paterson uses is honest and age-appropriate. Complicated things happen, but they're always described with the kinds of words her characters would use. Jess might drink coffee and struggle with adult topics – frustrated ambition, desire, and, finally, grief – and Leslie's parents treat him and Leslie like adults, but they are still in elementary school. Even as they co-create a complex fantasy world, they're also forced to deal with bullies on the bus and do what they regard as stupid homework assignments.
In writing a book like Bridge to Terabithia aimed primarily at an audience of children, Paterson reminds her readers that tragedy, joy, love, and grief happen to us no matter how old, or young, we are. Jess isn't old enough to drink, or smoke, or vote, or even to drive a car. But he is old enough to have an amazing friendship, to love his friend, and to realize what that friendship, and that friend, gave him. For more on how the book was received as Children's Literature, see the "Intro."