Of-course you can! If you are meeting all the following criteria, then you can definitely start working right away.
- You know HTML, CSS and JS.
- You know a programming language (RoR, PHP etc)
- You know how to handle dev-ops.
- You have a decent design sense. It's very very important in this modern web. Design is the key to win. Believe me no-one looks at your source code. 😉
Tu es prêt.