There's still a little bit of confusion surrounding the difference between web design and web development, but just to add my two cents - if you would like to create web pages which allow users to interact with the site (and many web users expect that as a given these days), then you will need to learn how to use advanced CSS (Cascading Style Sheet) properties, code libraries (JQuery etc.) and Javascript (which is code rather than markup).
There are also technologies which are specifically used to handle data (PHP, SQL), but that tends to be the domain of 'back end' developers.
Basically, what I am saying, is that designing web pages can be really satisfying and interesting, but due to the sophistication of emerging web technologies which provide individuals with a 'rich' user experience, not to mention the number of different devices that users are accessing web content with, web design/development can get pretty complex!
This may be an exciting prospect for you though, particularly if you enjoy the variety of learning lots of different web technologies, and are able to combine a creative approach with logical thinking. There's loads of learning resources out there when it comes to web design, appropriately enough, many of them are on the web! Start learning some basic HTML Markup and CSS properties if you haven't already, and also start looking into the developer tools built into the browser, and project software which enables collaboration such as GitHub. That should give you a good head start.
Good luck with your applications!