The star of the film version of novel The Hate U Give has admitted she found it hard to have her casting queried because she is not darker-skinned.
"It was the first time in my life that I'd ever had my blackness questioned," Amandla Stenberg told reporters at the Toronto Film Festival.
"I've never thought of myself as not being black enough," she went on.
The film tells of a girl who witnesses the fatal shooting of an unarmed friend by a white police officer.
The incident makes her question her place in both her predominantly black community and the private school where she is one of few non-white students.
She also faces opposition over her determination to testify against the police officer responsible.
Last month the artist who illustrated the cover of Angie Thomas's best-selling novel said she "wasn't exactly thrilled" by Stenberg's casting.
"I was hoping it would be a very brown-skinned actress, because there's so little opportunities in these big movies for darker-skinned actresses," said Debra Cartwright.
Her comments followed a debate on social media over whether the film was guilty of colourism - prejudice against people with a darker skin tone.
Speaking on Saturday, Stenberg said she was sympathetic to that viewpoint and had considered turning down the lead role of teenager Starr Carter.
"I have a great sensitivity towards the place from where that [viewpoint] comes, a place of pain," the 19-year-old said.
"It's a result of people being frustrated because they're navigating a colourist system at all times.
"There was a point in time when I went to Angie and said 'If you agree with these concerns and feel I don't accurately represent Starr, tell me and I will drop out'.
"And she said, 'What?' She said she had never questioned I was not the right person."
More from the Toronto Film Festival
Hunger Games star Stenberg has drawn praise from critics for her work in the film, which opens in the UK on 26 October.
Speaking on Saturday, Tillman Jr said he had wanted to make the film as "honest" and as "authentic" as possible.
The director of such films as Soul Food and Biggie Smalls biopic Notorious said he hoped it would both "inspire and create dialogue".
"I never wanted this story to be sanitised," said Thomas of her 2017 debut novel, which was inspired by a real-life police shooting in 2009.
"Angie wrote an amazing book with a lot of depth and heart so our main goal was to capture that," said Stenberg, adding that she hoped the film would make young black women feel "validated, empowered and strong."
Analysis by BBC entertainment correspondent Lizo Mzimba
One of the things a successful launch at Toronto can do is to make a film part of the Oscar conversation.
The audience reaction at the world premiere of The Hate U Give was sensational and word of mouth from subsequent screenings here has often been equally positive.
The film has its flaws but it gets a huge amount right, particularly an Oscar-worthy central performance from Amandla Stenberg.
If its momentum continues it's a real contender for the Festival's Audience Award - previous winners include Slumdog Millionaire, La La Land and Three Billboards Outside Ebbing, Missouri.
A film like this isn't usual Oscar fare, but the Academy is changing. Around 900 new members - with a significant proportion of women, ethnic minorities and younger people - were added this year.
could help The Hate U Give, already destined to be a box office hit, to also become a best picture possibility at the 2019 Academy Awards.
The Toronto Film Festival continues until 16 September.