Having the technical skills is only one part of being able to make a living online. You need to have a solid understanding of business (marketing, client acquisition, accounting, taxes, law, etc.), because that's exactly what you want to develop- a business that provides you with enough money to live, not only for today, but for years to come. That means you not only need to have enough revenue to cover your monthly expenses, but you also need to earn money for savings against lean times as well as savings for retirement.
Ooh, a red flag. I'm not against youth (it was an affliction that I and everyone else here suffered from at one point :) ), but youth often means inexperience. How much work experience do you have in the real world? Part-time jobs in high school rarely give much exposure to the real corporate world and how businesses actually work. It's very difficult to learn how to work for yourself until you work for others. The enthusiasm and energy associated with youth can help makeup for inexperience, but only so far.
I'm not good with people
Ooh, another red flag. If all you're going to do is keep to yourself and develop your own content and never have any customers, employees, partner, investors, or advisers (very rare, unless you keep your business small), you may be okay. But realistically, you will interact with a lot of people in your business. You need to learn how to work with them, how to negotiate, and how to motivate them.
Forget everything you ever heard about getting rich with AdSense. It rarely happens, and it certainly doesn't happen overnight. Yes, it is possible to make a decent living with AdSense (and/or other advertising), but it takes a long time to get to that point. And you are always at the mercy of Google (or other search engines) for traffic. If you look through the AdSense forums, there are MANY "Google banned me!" threads.
My advice is that while you build up your online business, get a day job (or don't quit the one you have if you have one, especially in this economy!) and build up work experience. Not only does it give you cash to live on while you build up your site, but it also builds skills that will be critical in life. While doing your day job, don't just go through the motions- try to understand every single facet of the business, from dealing with customers, marketing and advertising, hiring/firing employees, and paying employee benefits and taxes.