On dropping out of high school!?

NOOOOOO do not do it. You would not be able to stay in London long enough to write a column let alone a novel. The years of Americans escaping to explore their art is long gone. You need to check the rules for living and working in any foreign country. If you are a Freshman you can still learn a lot from your English teachers not to mention great novelists have lived a life longer than a freshman. Sorry to be blunt but you need to finish high school and then think about learning as much as you can in college about writing. Your life will be richer honest.