Every newspaper needs reporters.
Go to an event, take pics, write a story, and submit them.
Editors want someone they can rely on to deliver good articles within the publishing deadlines. Its better to do one good story on time with a good lead sentence than a great story late with a bad lede. And you have to do it every week or day.
A small local daily or weekly or alternative weekly is the place to start.
The other thing a good jr reporter needs, is a good editor - mom or dad or another adult to look the story over.
Its fine to focus on kid stuff, but the adult stuff is the bread and butter.