Hi CD and welcome in :)
Practice practice and more practice. Help out with food preparation at home when ever you can - practice using knives on veg and fruit wherever you can. You've come to the right place if you need info and advice, people here are more than willing to help. Also, you can search the threads and archives here for many things which you may need info on. But as with most things in life, getting hands on experience is the best way for your hands to learn the task.
Its great to see a young person with such a passion to get moving into cooking. My love of cooking (I don't do it for a job any longer) started with a part time job at your age as dishwasher in a kitchen, and I was fascinated by the hustle & bustle & routine of the pro kitchen. I did real drudge work. Cleaning out the fat traps, cleaning the hot plate at the end of service (ouch!), sweeping the floor, etc etc - kitchen donkey :) But what it did give me was a love of the routine and discipline and the love of how the heck the chefs and cooks produce what they do in the time frame.
I went from there to simple things, veg and salad prep, stock taking, stock rotation, breading schnitzels for big functions, things like that. Repetetive yes, but its amazing what you pick up just from being there, listening, asking people about things you don't know (but NOT when they are busy - they don't like it and haven't got the time, you gotta ask in a slow moment). It will grow you up more quickly than you can imagine.
Eventually after a few months I was pretty much in charge of the salads and cheese and fruit plates, soups (it was in a university cafeteria for the lecturer's), and got to cook the bosses' dinner each night. Now that was easy, he ate the same thing every day - T-bone and tossed salad. Silly man, no imagination :) My chef was a tiny feisty Italian lady and I miss her - we got on famously. Her sous chef was a big gentle man who would create magic with what seemed no effort. And the other kitchen hands worked well together as a team - when all the customers were gone we'd crank the radio up and clean down. Exhausting days but great fun.
So, if its really what you want, to cook, pursue it. Practice, read, ask questions. It can take you anywhere in the world once you know what you are doing, Explore the possibilities and use your imagination - but be patient, it doesn't happen overnight.