If you're interested in building your own website, or developing a web app or service for others to use, you'll need to get familiar with how the web works and the tools you'll need to develop for it. Mozilla's Webmaker project can help you learn, with fun, interactive activities and lesson plans designed for people of all skill levels.
Webmaker is actually a global project by the folks at Mozilla designed to teach people web literacy — that is, pull back the veil on how the web works and your favourite sites and apps function, and so you can learn to build for the web yourself. The general idea, according to Mozilla, is that there's no better way to learn the mechanics and culture of the web than by playing around and hacking it in a safe, fun environment.
The Thimble editor just picked up an educational award, and the whole project is designed to break from a simple curriculum of lessons (a la Codecademy and the like) and instead focus on getting hands-on with web design and development. If you're interested, or thinking about building your own website or webapps, it's worth a look. Hit the link below for more information.