The great thing about web design is that you can start today! If you have a computer and internet access, you can get started. You can watch youtube.com tutorials and get familiar with the programs used. You will have to research many types of software and websites that can help you. Web design is part art and coding. Eventually, you can build websites for yourself, your friends or a cause you care about. Many people start by building a website for clubs at school or their church. You need to build a portfolio (a few websites) to show a college or at a job interview.
The man in the link below started learning at 14 and was able to turn it into a business after one summer! The video walks you through how to start and at the end lists website where you can learn for free. How to Become a Web Designer in 2015 | Design Careers Roberto Blake https://youtu.be/qSQQc6R35kw