Agreed with the above that you should play the junior tournaments that your schedule will allow to build up some competitive golf experience. Do you play on a high school team?
I took up golf seriously at 14 and couldn't break 100. By 18 I was headed to play college golf with a plus handicap. It takes a ton of dedication and, even if you don't make the "tour", you're going to acquire some seriously valuable skills along the way.
The best piece of advice I can give you: Get a job at a quality golf course. Some place where you can get to know the pro and the skilled players that are members there. Find a place that will let you hit balls until you fall over dead and play/practice before and after work. If you have financial means, I guess you could just join such a course, but believe me, waiting and working that 8 hour shift in the morning will build up a good amount of hunger and dedication for your practice session and round in the afternoon.
-make sure you're playing the proper equipment. Get fitted for your clubs. Learn all you can about clubs and how they work. A quality pro shop job could help you learn how to regrip and take care of your owns sticks.
-Find a fitness routine. If you really want to make it "big", you need to be in shape. Few guys out on the tour arent in tip top physical conditioning.
-Balance: Golf is not your life, even though at times it will seem like it. Play an additional sport such as basketball that requires different physical movements than golf does. It will help your body develop and can break up the monotony of playing the same sport year-round. --Given your current skill level, you are likely too old to play college golf for a major D1 program. Top programs recruit kids that are top junior players from a young age on up until they are ready for college. There is NOTHING wrong with this fact at all, plenty of golfers have either played for a smaller school or not played at all. By the time you are 18 you might be a great, great player and the fact that you will feel slighted/overlooked will only fuel you to hit those extra shots on the range or make an extra 20 5-footers before you call it a day.
-On that last point, learn HOW to practice. My coach always said to "practice with a purpose"... aim at the flags on the range. Practice all kinds of shots. Make X number of putts from a certain distance before moving on. Practice putting pressure on yourself. Drop 10 balls around a practice green in all types of distances and lies. How many of the 10 can you get up and down?
Lastly, enjoy yourself. Golf is a game but it also a life skill. Be proud of the progress you make. You are young and you have the opportunity do something that money cannot buy: to make a future for yourself in this wonderful game. Good luck and keep us updated on your progress.