This completely depends on your practice, proficiency, and dedication. The more you hone your skills, the faster you can establish yourself as a professional web developer. As website development focuses on lightweight codes, it is easier to master than other languages.
With regular practice and commitment, you can learn the basics in a few months. Once familiar with website development fundamentals, find a job where you can upskill yourself and seek experience while working on real projects. You will soon learn to find bugs and fix errors, which will add to your expertise. As you will become better at debugging and solving technical glitches, you will find more lucrative and promising jobs.