Here are some great ways to start. (Click the picture to visit the site.)
If you haven't ever done anything coding-related, I'd recommend trying:
SCRATCH: A basic way to make basic games and slideshow-type things with code blocks. Great for beginners (and fourth graders).
HOUR OF CODE: Take an hour of your day and learn how to use basic code with the likes of Minecraft and such.
If you want to start with real code or you've already tried that:
KHAN ACADEMY: There's a great course for learning code, and it even tells you your mistakes. How cool is that?!
CODECADEMY: This is a website for learning code. There are plenty of courses for many different kinds of code, like HTML5 and JavaScript.
I WANT TO EMPHASIZE THAT once you learn one programming language, it's a lot easier to learn the rest.
Now, programming, as an industry, is growing rapidly, and knowing how to code is an important skill to learn. The need is growing, too. If you like ROBLOX, then learning how to code can award you a front-page deserving game. Ooo, cool.