If you're interested in joining a writing community, you don't have to wait for college. Your high school may already have a writing club that follows some of the practices of writer's workshops and literary salons. If not, you can most certainly find a summer program for young writers at a college, university, or creative arts center near you. The first of these types of programs was created in 1983 at the University of Virginia. More than thirty years later, the program is still going strong, offering students like you the opportunity to study with published authors and build a writing community of peers who live all over the world.
Following the success of UVA's Young Writers Workshop, other colleges and universities developed similar programs. There are so many now that you probably would not have to travel very far to participate in one. Some are day programs, while others are residential "camps" that require a bigger investment of time and money. Almost all of these programs have an admissions process designed to determine if would-be participants are a good fit for the program. (The essential qualification is that you're dedicated to becoming a better writer and learning from other writers--adults and people your own age.)
Take some time to explore the kinds of writing workshop communities available to writers your age: Click the Activity button, and complete Section I of the Writing Communities WebQuest, which will ask you do some online research about summer writing programs for teens.