Even J.K. Rowling has her doubts.

In a series of Twitter posts earlier today, the Harry Potter author, who is now worth an estimated $1 billion, hints about how she had her doubts about whether to keep writing in the 90s. In response to a tweet that read: “You’re working on something and you’re thinking ‘Nobody’s gonna watch, read, listen.’ Finish it anyway,” she wrote:

But she stresses that keeping on keeping on is the way to go — even if your art never finds a single fan.

Discipline, she says, is something you can “truly take pride in.”

Admittedly, making your dreams happen may take time, she says.

But even if it takes years — or never happens at all — it’s probably worth it.