That's the age when I really started coding. Now I'm in my second full-time programming job and building a pretty great resume.
My tips:
1) Study and practice. Pick a topic you don't know, choose a book that's well reviewed, and learn it.
2) It's better to ask a dumb question than to never know the answer.
3) Do a bit (not too much) of reading on things like HN and JoelOnSoftware, etc, to help you pick what to study next. (Like when I read Spolsky's argument for why distributed version control is better than centralized, I eventually decided to learn Git. Or when I saw all the buzz about Rails, it pointed me that direction.)
3) Learn the crap out of your tools. I started out with a Windows HTML editor. A couple years later, I was using Vim in Unix and I'm way more productive. But I'm still learning new stuff about it every day. I intend to know it backwards and forwards eventually.
4) You'll never know everything - don't get discouraged.
I was a journalist, and unhappy. Took a break, went back to school (to study music), met a girl, and we decided to get married. By that time she was in grad school a few hours away. When we married, I moved there and had to find a new job.
I knew HTML and got a job doing tech support for cell phones. My employer had no internal web site and I saw that they needed a page to share links to reference sites, so I made a simple HTML page, just dropped onto a shared file server, not even a web server. Then I started adding pages of training material, etc.
I had just heard (this was 2007) that CSS could be used for layout - gasp! - so I bought Eric Meyer's CSS: The Definitive Guide and studied during lunch breaks and evenings. I spiffed up the site. Next I got Head First Javascript to add some animated menus. Soon after, somebody told me about jQuery, and eventually I caught onto that.
As I added more pages, it sucked to have to copy and paste my common menu, so a friend recommended PHP. I had to set up Apache for that, though, so I used XAMPP. Now I could do includes! But wouldn't it be nice to have some database interaction? I read a PHP book and added that too. Eventually the system was pretty complex, with object-oriented database interactions, permissions controls, AJAX widgets, etc.
All this time I was getting advice from my best friend (we were roommates in college), who is a truly awesome coder with famous companies on his resume. And I was discovering that I really enjoyed this stuff and had a knack for it. Also, all this time, I was still doing tech support: I could be knee-deep in a coding problem and get a phone call, and I had to pick it up, and it might take 2 hours.
But by the time I left, I had a good enough resume to get a full-time programming job. And I continue to learn. I've made the jump to Ruby and Rails (Ruby is a lovely language), test-driven development, etc. I'll never be DHH or Linus Torvalds, but I hope to do solid work and keep having fun.
My tips:
1) Study and practice. Pick a topic you don't know, choose a book that's well reviewed, and learn it.
2) It's better to ask a dumb question than to never know the answer.
3) Do a bit (not too much) of reading on things like HN and JoelOnSoftware, etc, to help you pick what to study next. (Like when I read Spolsky's argument for why distributed version control is better than centralized, I eventually decided to learn Git. Or when I saw all the buzz about Rails, it pointed me that direction.)
3) Learn the crap out of your tools. I started out with a Windows HTML editor. A couple years later, I was using Vim in Unix and I'm way more productive. But I'm still learning new stuff about it every day. I intend to know it backwards and forwards eventually.
4) You'll never know everything - don't get discouraged.