Couldn't be happier that you're interested in web development. I like some of the other answers I see, but I feel like there are still major pieces missing to the puzzle.
Don't get into development for the wrong reason.
I fell in love with development when I was 12. Not because I wanted to be an internet entrepreneur and make the next greatest thing, but because of the instant gratification development often provides. There is no feeling like being able to fiddle with a few lines of code and drastically change what you're working on and not having to wait more than a refresh or a build to see the outcome.
While doing client work, it was often that I was being called because the client had attempted to build something on their own (spending quite a bit of their own time and making a lot of personal sacrifices) and wasn't happy with the result because they didn't turn out to be the developer they had figured they would be. (HTML for Dummies said they would be an expert in no time, after all!)
Bottom line here is: if you don't genuinely have a passion for at least one of the countless aspects of web development in its entirety, then I would take a step back.
If you are intrigued by web development and want to make a career out of it...
Understand what web development is and where you expect to be. As mentioned above, there are a million different aspects to web development. You can create your own projects without leaving home, from anywhere in the World. You can do SEO Solutions in Toronto or to open your own online store in Los Angeles.
Are you making a small blog? Cool, WordPress and a $5/month web host can get you off and away with little to no HTML/CSS experience.
Are you thinking of building a small web community that no existing CMS or software can handle? Well, you're going to need a server-side language to handle interacting with a database, handling user requests and keeping track of a user's session. If you plan on doing anything with Ajax on the front-end, you'll also need the back-end language to build web services. Then, of course you'll need to know HTML to put stuff on a page in a way that is understandable to your users, and then CSS to make it pretty, and then JS to handle interactions, Ajax requests, and/or special effects.
Are you thinking that you want to launch a huge corporate website that handles a crazy amount of traffic? Your first problem is getting to this point (and if you're at this point and don't have a team to handle the different responsibilities then you might be sleep deprived and should see a doctor). The second problem is on top of everything mentioned above, you need to understand the IT portion to handle multiple servers, load balancing, etc. You're probably going to run into performance issues so you'll need a caching architecture to handle serving common content repeatedly without constantly pinging your production database. This could continue on...
Where you fit in...