A start-up is unlikely to have things done right and can be the worst place to learn good practices. Back in the days I knew people who were just working with

A start-up is unlikely to have things done right and can be the worst place to learn good practices. Back in the days I knew people who were just working with startups and didn't know about testing or versioning. Most startups have zero documentation. In my experience you're as likely to find good people in startups or in established companies. It's luck, knowing someone who know someone. Experience in the industry is useful. That said you can learn just as much if not even more just starting and failing. Just never stop learning and eventually things will be alright