I do not have all the details, but young people go get "home schooled" and it is legal. Here is  link to get you started.

One of the beauties of homeschooling is that the learning can be tailored to meet the needs and learning style of the student.  There are so many options available from online high schools, to programs that provide the materials and let the parent(s) teach, to materials that you can assemble into lesson plans yourself.  There may be homeschooling groups in your area that offer things like shared teaching (a parent with a strength in a particular subject may teach a small group of students) or just opportunities to network and learn more about home education.  Google, your local library, or popular bookstore can be helpful in seeking one out.  It is important to find out what your state and local laws are regarding homeschooling if you decide to pursue this option--laws can vary greatly.