I have not enough experience with iOS/Android development to know, but I wonder if it isn't somewhat more easier to learn iOS for instance since it's just one language and IDE you have to focus on, while for web-dev you need to learn multiple languages. (Though at a certain point you'll need a server-side language to give your app the ability to communicate with a server...)
> If you're starting from scratch, learn HTML and CSS and make some simple static pages. Then once you're comfortable, learn a high level language (eg. Ruby or Python). Then learn a web framework for that language (Rails if you're focusing on Ruby, Django if Python). You'll probably want to pick up some Javascript too.
Exactly what I was thinking, but you gave actually steps.