Here are some resources for information about undergraduate publishing opportunities in English.
And creative writing...
This links to a young writers resource. Pay attention to the guidelines and age requirements. http://www.newpages.com/npguides/young_authors_guide.htm
You probably haven't, but that's okay. http://opinionator.blogs.nytimes.com/2014/05/05/the-perfect-essay/?_php=true&_type=blogs&_php=true&_type=blogs&src=me&ref=general&_r=1