okay, let me think...
19? Start out working and studying as much as you can, spend time in between with family and close friends to keep your social life going.
Get a job that requires a lot of responsibility and pays you pretty well, but nothing too far stellar at the moment.
There are a lot of high paying jobs out there for even young people like yourself. You have to be willing to search for them, they usually just don't come crawling to your door step.
Let's say you have year 19 to experiment and to learn as much about 'everything' as you possibly can. And set a goal that by the time you're 20, you have to start saving like mad, but does not completely mean cutting your living style into ramen noodles and bike rides to work, but does not limit you to being somewhat thrifty and conservation-minded.
By the time you're 20, you want to make it to your 22nd birthday with $25,000? So that's 24 months. Split evenly every month, you're looking at saving a little over thousand dollars, $1,050 to be more exact. Otherwise, if you started at 19, that's $700 a month over the course of 36 months to get just above $25K.
Now there are administrative-assistant positions that allow you to get paid anywhere from $30K/year to +50K/year. But we're talking about professional nirvana even if you're still enrolled in a school and don't have a college degree like the guys/gals that are 'up' there.
There are people your age who are millionaires or have hundreds of thousands of dollars on them because they decided to invest at an early age. However, don't let this thought hinder your performance, but may it help remind you as sort of a motivator for constantly looking at success through the end.
If you're hardcore series, time to visit a library and start studying. Knowledge isn't power unless you know how to utilize it. Don't hesitate to take statistics/management/money/financial analysis/etc. courses in college, they will definetly pay off in the long run. Good luck!
p.s. a dead end job that pays you scraps is only the beginning, it teaches you how to work hard at the start, but after you've had it, if you haven't learned anything, you better hit the books harder~ have fun!