Have done design/development since i was 16, I'm 26 now....didn't take it too serious until my early 20s though and am just now feeling like a jedi master haha.
There are so many specialty/niche fields in development. If you are trying to learn it all; i'd say start with learning how to write valid html markup/css; once you mastered that pick a cms/framework and learn how to develop dynamically with a backend(i use php/wordpress for smaller projects and ruby on rails for larger MVC ones). After that learn how to program jQuery.