Nicole Maines, the Maine schoolgirl who won a landmark court case in 2014 for transgender rights, broke another barrier this weekend when it was announced that she will be the first person to star as a transgender superhero on a network TV series.

“I haven’t quite taken it all in yet,” Maines, now 20, said in an interview Sunday night during a conference call from Canada that included her father and manager. “It’s beyond anything I could have imagined.”

The news that Maines had been cast to portray a reporter on the Warner Bros. “Supergirl” series on CW came Saturday during the geek culture extravaganza known as Comic-Con, which was held in San Diego. “Supergirl” announced that the transgender activist and actress would play Nia Nal, also known as the superhero Dreamer.

Maines was born a boy but identified as a girl from the age of 2. She was a fifth-grader in Orono when she and her family challenged the legality of the school administration’s decision not to allow her to use the girls bathroom.

Actress and advocate @NicoleAMaines discusses her landmark casting on #Supergirl as transgender superhero #Dreamer. #SDCC #IMDboat pic.twitter.com/E4J0E5aE2S

— IMDb (@IMDb) July 22, 2018

In January 2014, the Maine Supreme Judicial Court ruled that school officials violated state anti-discrimination laws when they required Maines to use a staff restroom. It was the first time that a state supreme court had affirmed a transgender person’s right to equal access to restrooms in places of public accommodation.

In the interview Sunday night, Maines said she will begin filming “Supergirl” this week in Vancouver, British Columbia, where she will live for the next several months. Filming is expected to end in April.

Maines, who recently finished production in Los Angeles on an indie film titled “Bit,” said she had to audition for the role on “Supergirl.” Quite a bit of time passed before the show’s producers called her back, a period during which she thought that someone else had been cast.

She got a callback while she was still filming “Bit,” a horror film in which she is cast as a transgender teenager trying to coexist with and understand a group of feminist vampires.

“I guess I did something right,” Maines said, referring to her new role on the popular CW show, which is heading into its fourth season.

Producers describe her character as a “soulful young transgender woman with a fierce drive to protect others.”

The show tells the story of the character Supergirl, also known as Kara Zor-El, who decides to embrace her superhuman abilities. Kara works as a reporter at CatCo Worldwide Media, according to a description of the show posted on the CW network’s website. Maines said she will appear on the show as a newly hired reporter at CatCo whom Kara takes under her wing.

“Nia Nal has this fierce drive to protect people who have been marginalized,” Maines said. “I think that is what will drive her to pursue her superpowers.”

Maines said she is feeling a little nervous about her groundbreaking role and about striving to ensure that she represents the person who the show’s producers believe she can be.

But her father, Wayne Maines, has no doubt his daughter will do a super job of portraying Nia Nal. He describes her as poised and fearless.

“She has been interested in acting since she was a baby,” said Maines, who recently moved to Austin, Texas. “I’m extremely proud of her.”

Maines, who is 60, admits that he has not watched “Supergirl” in the past. He is playing catchup with the show.

“I just started watching it,” he said Sunday night. “I’m on my third show. It’s very good.”

Nicole Maines was the subject of The New York Times best-selling book “Becoming Nicole: The Transformation of an American Family.”

She made her TV acting debut three years ago in an episode of the USA Network series “Royal Pains,” in which she played a transgender teenager.

Earlier this month, Hollywood actress Scarlett Johansson withdrew from the film “Rub & Tug” after her plans to portray a transgender man prompted a backlash. Her casting in the film came at a time when the LGBTQ community and its allies are encouraging directors to cast transgender actors in transgender roles.

Wayne Maines and his wife, Kelly, have another child, Jonas, who is Nicole’s twin. After Orono, the family moved to Portland, where Nicole graduated from Waynflete in 2015.

Wayne Maines praised the private, coeducational school for giving his child the support she needed. On its website, Waynflete says, “We deliberately create an environment where children feel safe and supported no matter who they are.”

Maines and his daughter are grateful to the people in Maine who supported them through some difficult moments.

“I want to thank them for their overwhelming support,” Nicole Maines said. “We started this journey because we wanted to protect our family, and now it’s nice to see that we have affected people’s lives in a positive way. Hopefully, we are going to continue to do that through my role on ‘Supergirl.’ Hopefully, we can make life a little easier for transgender people.”

Steven Simon of Landis-Simon Productions and Talent Management, which is based in California, is Maines’ manager.