'I haven't really wrapped my head around it, ' she said during Variety's panel.
LGBTQ advocacy organization GLAAD in 2017 identified only 17 regular and recurring trans characters on television.
Maines hopes her role in the DC show will provide a positive impact and the "right representation" for the trans community.
Maines' awareness of the societal stakes of representation is clearly on her mind: "I think we're in a time right now where more than ever representation in the media matters", she said. "And what we see on television has a very dramatic effect on our society".
Maines referred to cisgender men dressed in women's clothing as the only representation she saw growing up in the 90's and early 2000's. Per a description, Maines' character is "the newest addition to the CatCo reporting team".
Cristiano Ronaldo leaves huge tip before Juventus unveiling
The Brazilian sent an emotional tribute to Ronaldo after the five-time Ballon d'Or victor penned a four-year contract with the Italian champions.
How does the star feel about Scarlett Johansson's controversial exit from Rub & Tuck where she would have played a transgender man? Fans may also be familiar with her story from the book Becoming Nicole. "We've seen that. But trans people have lives outside of our gender identity and our transness".
"I think that cis gender actors don't take roles out of malice, it's just a failure to realize the context of having cis gender people play trans gender characters".
While there were reports a couple of months ago that Supergirl was casting a transgender character, yesterday's announcement made those reports a reality and helped the show break even more ground by casting Maines, who is herself a trans actress, in the role.
CBR also pointed out that the Legion of Super-Heroes comic also introduced a transgender character in 1992 in the form of the scientist Shvaughn Erin, Element Lad's romantic interest, who took a drug to changer her sex from male to female.
Just how Nia will factor in with the chaos and mayhem threatening to destroy the Earth (yet again) remains to be seen, but it's safe to say that when Supergirl returns on October 14, she'll be out there kicking alien ass and taking names with the best of them.