The aim is to "Write a text adventure that is suitable for beginners to this genre. The game must include an in-game tutorial."
The games in the first Text Adventure Literacy Jam in 2021 were aimed at children, but that is no longer the case. Rule 12 says, "Any game with adult content must have a content warning at the start of the game." The Content guidelines elaborate on this and suggest that "It is preferred that your game is G-rated (suitable for a general audience) and would appeal to children." This is the only time that children are mentioned.
So, it must be written for beginners to text adventures, but it would be nice if it also appeals to children, as children are often beginners to the genre.