LONDON -- Former US first lady Michelle Obama expressed confidence on Monday that the social progress made by having the first black couple in the White House could not be overturned.
Without directly addressing her husband's successor, Donald Trump, Obama said change was "not a straight line" but the election of Barack Obama to the White House showed people were open to change.
Earlier in the day she encouraged some London schoolgirls to ensure they played a role in tackling the "the bitterness, the nastiness that we see in politics" by never wasting their vote.
Obama, 54, said she was surprised as anyone when her husband was elected the first black president, taking office in 2009 - especially because when "he was elected he looked like he was 12" - and hopes were high.
"We mistakenly thought Barack Obama was going to erase hundreds of years of history in 8 years," Obama told a full house of 2,900 people at the Southbank Centre's Royal Festival Hall as part of a tour to promote her memoir "Becoming."
"We made progress and going backwards doesn't mean it wasn't real," she said, adding that actions taken now helped to pave the way for people's grandchildren.
Receiving a standing ovation as she strode onto the stage, Obama spoke about everything from convincing her parents to let her eat peanut butter for breakfast, to her father talking about the joy of sex, to dealing with his death in 1991.
She also joked about breaking protocol when she touched Queen Elizabeth, wanting to sometimes push her husband out of a window, and her drive to protect her 2 daughters, now aged 20 and 17, from the public spotlight and online attacks.
But she also had a serious message about the need for girls to get a good education and to overcome self-doubt - particularly young black girls.
Earlier this year, Obama was named the world's second-most admired woman, behind Angelina Jolie, in a YouGov poll, but she said she still sometimes questioned if she was good enough.
"I still feel at some level I have something to prove because of the color of my skin, the shape of my body," she said.
"My advice to young women is that you have to start by trying to get those demons out of your head," she said.
"Your task is to get yourself ready because people will try to hold you back ... it will crush you if you are not ready."
Obama, who brought up in a working class family in Chicago, said she watched girls strive as she had and she would continue her campaign for girls' education that became a passion while in the White House alongside her work on childhood obesity.
Returning to a central London school for girls - Elizabeth Garrett Anderson - that she first visited in 2009, Obama encouraged students to find their passion, mentors, and help each other, adding "there's no room for mean girls".
Obama said it was important to give young people a reason to hope, particularly in the current divisive political climate.
"The one challenge we have ... is harnessing the power we do have and not relinquishing that and by that I mean voting," Obama, a graduate of Princeton University and Harvard Law School, told 300 rapt teenagers.
Asked often about her political ambitions, Obama makes it clear in her book she has no intention of going down that route.
"I have no intention of running for office, ever," she wrote. "I have never been a fan of politics and my experience over the past 10 years has done nothing to change that."
While Obama has not criticized Trump directly at events to promote her memoir, she does criticize him in the book.
Trump with "his loud and reckless innuendos" about her husband's birth certificate put "my family's safety at risk."
"And for this, I'd never forgive him," she wrote.