Lizzy Milani has a great article about knowing God's purpose for your life at Fevr.net.
I remember being obsessed with this when I was a teenager. Now that I'm older (and wiser?) I don't think there is just one right path for you. As a teenager you have many choices and decisions to make - especially about what you are going to do after high school. Romans 8:28 says, We know that in everything God works for good with those who love him, who are called according to his purpose. That means in everything, our good choices and our not so good ones. Lizzy closes her article with this statement, Don’t be afraid of mistakes... they are our great teachers, a classroom of wealth and a way to figure out the path forward. God certainly is not afraid of them... He can turn ANYTHING around for good. So the only mistake you can make is not letting God in on the journey.
Short and sweet inspirations for Christian teen girls.