Well I don't want to spoil your moment of glory for you, but 17 is not really adulthood in my opinion.
Sure, you may feel like you're an adult and mature, and want to decide where your life is going, but the truth is that you have years before anything like that becomes anything of consequence.
Take for example the path I took. When I turned 17, I too felt the throngs of adulthood within my grasp. I made plans to go to college and made decisions that I thought would put me on my path through life. I went so far as to work hard to make it to the National Honor Society, graduate in the top 10% of my class (500+ students), and applied for colleges.
Somewhere around the age of 18 (end of my senior year) I had settled on going to college for computers with a minor in theatre arts (technical, not acting). I was so sure and I had already been accepted to college, but for some reason completely put off registering. At the time I was working in a theatre doing lighting and audio work on the stage and we put together three shows for the summer. It was the most fun and rewarding experience I had.
Towards the fall of 2005, after graduating from high school, I was getting ready to register for college, but never did. The registration packet just sat on my desk for a couple months. Something didn't feel right about going off to college. I just didn't have the commitment or desire to sit in school for four years. Instead, I was offered a job as a Network Operations Engineer for a small (at the time) internet service provider/webhost. I was responsible for installing, configuring, maintaining, and building servers and networks. I dabbled in all kinds of software, operating systems, network equipment, and tons of other things.
With the level of technical expertise and experience I had after working there, I knew more about networking than any college student with a Bachelor's degree. That was only after about two years. From 2005 to the end of 2007 I worked there, and then I decided to enlist into the US Army.
Currently, I serve the US Army and I was already deployed. In 5 months I ETS and return to a civilian life, as well as a job in the IT industry and hopefully, with my last employer who is eager to rehire me. Since then, I have received several certifications via Army tuition assistance, am set to take a few more certification exams by June, and started my associates degree online (only a few credits so far).
When I was 17 I had no idea or inclination that I would have done and would be doing anything that I have so far. I am 23 now, and I have yet to "grow up" in that way, and some others. Obviously, since I love playing video games I will never completely grow up. However, I am a young adult, and I have a lot to learn and experience. Although, I no longer think that we all have one path in life.
From all that I have learned, I think of life like this:
Life is not about where you end up in life. Instead, life is about how you arrived at where you end up. No one has one set path, and it's the culmination of "detours" and paths that we all take.