Making the choice to start over in your 40s is never going to be easy. But sometimes, it's exactly what you need.

Hanna Rosin's piece Screw Mastery for Lenny Letter is the perfect example of how equally scary and exhilarating it can be to start a new career further down the track.

We all like to feel like we know what we're doing at work, like we've mastered our jobs. But when starting in a new career, it's important to let that fall away.

Rosin writes about the transition from print journalism into the unknown world of podcasts. "Every day I was exhausted, the way you are when you visit a foreign country," she explains about the work she put in to launch this new career. "You don't speak the language and everything takes too much time and the people don't act the way you expect them to and you are functionally a child. But the days go by fast, because novelty is a kind of drug." But beyond that, she also learned a lot. Not only about the new field, but about herself.

"I learned a ton of new things about myself, in the way you can only do if you are fucking up daily. I learned that I am defensive but trainable. That I have capacity for patience but that my immediate default is speed, bluntness, and ironic distance. That although I am used to working alone, I will happily collaborate. And that I really like working with women, even if they cry more during the day."

There are plenty of women, as well as Rosin, out there to offer inspiration. Take Martha Stewart, for example.

By the time she was 40 years old, she had already had three very different careers: she sold securities on Wall Street; she owned a catering company; and founded Martha Stewart Living Omnimedia. Stewart told MAKERS one of her mottos is, "When you're through changing, you're through."

Toni Morrison didn't publish her first novel until she was in her 40s. Julia Child didn't start cooking until 36. Vera Wang didn't design a gown until she was 40. Genevie Kocourek, an information technology director went back to school at 59 to become a doctor instead of accepting early retirement. And all of them went on to phenomenal success.

You're not going to know how to do everything. You might not even know how to do anything. That's what starting over is. It's the chance to learn and grow and be better.

So, like Rosin says, "Screw mastery."