Ask HN: When is a programmer good enough to freelance?

I started coding about two years ago (Python/Django). I've been employed as a web developer with varying success. I built my own personal website as a learning exercise and it's about to be deployed. I'd like to freelance to earn some extra income, but the last thing I want is to take on a job I'm not ready for and deliver a substandard product. This profession doesn't seem to have established benchmarks--how do I know when I'm ready to take on a project on my own?