Hey there! Have you heard about the Cybersecurity program at the University of Nebraska at Omaha? You should check it out! https://www.unomaha.edu/college-of-information-science-and-technology/academics/cybersecurity.php
Their student group NuLLIFY hosts a high school CTF competition every year. You can find more information at http://ctf.nullify.uno/. They will be hosting another high school CTF again this year. It is tentatively scheduled for November 18th, 2017.
Here is the website: http://www.unomaha.edu/college-of-information-science-and-technology/engagement/nullify-ctf.php