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WELLINGTON, New Zealand — A verdant island nation at the bottom of the world — one of America's closest allies — may have something to teach the U.S. about the role of women in public life.

Women in New Zealand could vote two decades before American women, the country is on its third female prime minister — and now the current officeholder, an unmarried 37-year-old named Jacinda Ardern, is about to give birth.

In June, Ardern, the world's youngest female leader, will become just the second woman in history to give birth while an elected head of state. She'll become the first elected leader ever to take maternity leave.

"I don't want to ever give the impression that I'm some kind of wonder woman," said Ardern, an unpretentious wunderkind with an ever-ready smile. "Or that women should be expected to do everything because I am. I'm not doing everything."

She'll have help with childcare from the baby's father, Clarke Gayford, her partner of four years. Gayford, host of a popular fishing show called Fish of the Day, is planning to be a stay-at-home dad.

The couple's unwed status, she said, was not a "deliberate decision."

New Zealand Prime Minister Jacinda Ardern, seen here at an Auckland festival in March, will be the first elected leader to take maternity leave. Hannah Peters / Getty Images

"It sounds terrible, because we're very committed to each other. [Marriage is] just not something we've really gotten around to."

"We haven't correctly sequenced, perhaps," she laughed.

"A girly swot"

Ardern describes herself as a nerdy overachiever — an "absolute girly swot" in Kiwi speak — from an early age. The daughter of a police officer and a school lunch lady from a farm town on the North Island, she threw herself into left-wing activism, joining the Labour Party at just 17.

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"My whole reason for getting into politics was because I had this strong duty to care for other people," said Ardern.

She cast her first vote for Helen Clark, who became the nation's second female prime minister in 1999. In 2008, Ardern became the head of the International Union of Socialist Youth, as well as the youngest member of the New Zealand's parliament.

Prime Minister of New Zealand Jacinda Ardern sits with her partner, Clarke Gayford. NBC News

Because of the women who came before her, Ardern said, she never had the sense she couldn't reach her goals.

"The sentiment in New Zealand," she said, is that "people should have a fair go. They should have a shot, they should have a chance to prove themselves."

Jacindamania

Another lesson New Zealand might be able to teach the U.S. about public life is how to disagree without demonizing.

Ardern became leader of the Labour Party just seven weeks before the September 2017 election. With an appealing political natural at the helm, Labour began a rapid rise from the depths of the polls, but on election day no party won a majority.

To form a coalition government, Ardern teamed up with the very conservative New Zealand First party. In American terms, that would be like Bernie Sanders joining forces with Ted Cruz.

Ardern agreed to give the leader of New Zealand First, Winston Peters, the post of deputy prime minister. He will be in charge of the country during Ardern's maternity leave.

Prime Minister of New Zealand Jacinda Ardern, right, with NBC's Cynthia McFadden. NBC News

New Zealand has an image as a South Pacific paradise, with breathtaking mountains and beaches and unique wildlife, but it has political problems that would be familiar to Americans, such as homelessness and soaring housing prices. Like the U.S., New Zealand also has political divisions — deep ones — and more than half of voters chose a party other than Labour last fall.

But unlike the U.S., the country isn't polarized. Even many of the people who didn't vote for Ardern seem to be rooting for her now, won over by her humor and candor.

Dubbed "Jacindamania," the post-election honeymoon is an added perk for the prime minister, who delights in the reactions of the little girls she meets. "If they see a woman in a job like this and it has an effect," she said, "then that's wonderful."

Ardern's priorities as PM include fighting child poverty and climate change, and she was critical of the recent U.S., French and British strike on Syria.

Yet as a candidate she engaged some issues similar to those in the divisive U.S. 2016 presidential campaign, albeit with a very different tone. She ran on cutting immigration, and has proposed making it harder for non-resident foreigners to buy local real estate. Foreign investment helped drive average home prices in the country's biggest city, Auckland, up to $1 million NZ, out of reach for many Kiwis.

But she said she was "infuriated" when the Wall Street Journal compared her immigration policies to Donald Trump's in a tweet. She's not building a wall, she said.

"We're campaigning to double our refugee quota," said Ardern. "We are a nation built on immigration. The suggestion that I was leading something that was counter to that value made me extremely angry."

Meet New Zealand's Justin Trudeau—except she's more like Trump on immigrationhttps://t.co/HXs3FfmrWe — The Wall Street Journal (@WSJ) September 5, 2017

On Thursday, the Ardern charm will be on display in London, where, among her other duties, she'll meet Queen Elizabeth at Buckingham Palace.

The queen is officially New Zealand's head of state. Headlines during Ardern's campaign suggested she wanted to "Ditch the Queen." She has said she believes New Zealand will become a republic during her lifetime — meaning the tie to the crown would be severed.

Asked how that might go over at the palace, Ardern laughed.

"[The queen's] response has always been these are matters for New Zealand," she said.

She said she won't push the issue, at least not now. Leading the country, having a baby and taking on the Queen might be too much even for her.