"She's untested," one of my colleagues said.
That's true. But then John Key was untested as a prime minister. Everyone is untested until they get a shot.
And that shot comes now for Ardern.
What I do think Ardern has, which is rare in politics, is authenticity. What you see is what you get.
David Shearer had it too when he came to the leadership, but he had some poor advice. He was told to roll out the party line at every media opportunity, and he lost his way. It wasn't him. He lost his realness, if you like. And, well, the rest is history.
Ardern, though, has it in spades. She just needs to hang on to it.
And although I think she already has political credibility, she does need to develop that further. She comes across well in the media as a spokesperson for justice, and a spokesperson for children.
But, sadly, she's attractive. I say sadly because that can work against a woman. God only knows why, but there are still some among us who believe beauty and intelligence don't go together.
Remember, for example, when she appeared on the cover of Next magazine? She was described as the country's prime minister in waiting. And, in a TV panel, former rugby league coach Graham Lowe agreed, saying she was - quote - "a pretty little thing".
Columnists went on to analyse her. She was labelled "vapid" by one. "Pretty vacant" by another.
Remember, too, when she and Nikki Kaye battled it out in 2011 in the Auckland Central electorate? That was dubbed "the battle of the babes". Never mind the politics. Let's focus on the aesthetics.
Ardern can't fight that. She can't change old minds and an old way of thinking. She's been in politics for some time now, and has worked as a senior policy adviser in London. She's got the goods. She's got the intelligence and the leadership potential. All she can do now is prove herself in the role and prove to the country she is a leader.
It's true. She is untested. But that test starts now.
