I had never heard of Kate Nash, the singer, songwriter, actor, and subject of “Underestimate the Girl,” a documentary by filmmaker Amy Goldstein. I’m now a fan. Nash is an irresistibly likeable subject, and she is a huge part of what makes the film so entertaining. This is a great doc that explores what it’s like to be a musician in the modern world.

This polished film tells the story of Nash, tackling the entire trajectory of her career. Starting from her first taste of superstardom at age 18 to a decade later when she is nearly homeless, the film offers an intimate look at the challenges, disappointments, failures, highs, and lows of an industry that chews up and spits out the very artists that are its lifeblood.

Nash soared to the top of the UK pop charts in 2007 with a platinum record, and struggled with the burdens of her newfound fame. After worldwide tours and international success, the outspoken and trusting musician was defrauded by her manager, dropped by her record label, and forced to take soul crushing odd jobs (like hawking comic book merchandise for an online geek shopping network). After she’s forced to sell off her clothes and move back home, Nash has a revelation and decides to take control of her life and career.

Goldstein’s affinity for her subject shines through, and her well structured film takes viewers on an inspirational journey of creative fearlessness. Nash uses her music as a form of self-therapy, an outlet to express life’s frustrations through her art. Her original lyrics reflect her real life, giving a personalized glimpse into an artist who thrives on creativity and receives joy from the act of performing.

It’s sad how the people she trusted took advantage of her trust and her talent, and the film addresses the highs and lows of, and the serious problems in, the music industry. As Nash herself says, being in the industry “has almost killed me, but I’m not going to die for the sake of being a f’ing pop star.”

It’s a discouraging career choice to be in a business “where the bad guy succeeds most of the time,” but the film hits the high notes when Nash decides to make her fans her record label and crowd fund an album through a Kickstarter campaign. She’s following her heart and making the music she wants on her own terms, taking big steps to turn her life around. During this time, Nash also decided to add acting to her resume and auditioned for the Netflix series “GLOW,” where she’s cast as Rhonda.

The music industry is a tough place for women, but Nash’s story ends on a happy note. The teenager who started her career on MySpace has successfully reinvented herself, is speaking out about the need for protection for artists, and is looking towards a bright future. This is a rewarding documentary about a person that you’ll root for from the start, and it’s hard to watch it and not instantly become a fan.