Needless to say, Sanna Marin’s Twitter account has been on fire. On Sunday the Social Democrats in Finland elected her prime minister, so congratulations have poured in from all over the world. That’s no surprise, as Marin is a record breaker. The 34-year-old transport minister and second-term MP will be the youngest serving prime minister in the world, and Finland’s youngest prime minister ever. The photo of Marin and her four fellow government party leaders, all women, quickly went viral. Obviously Finns are enjoying every minute of the international attention, but while the world is celebrating Marin’s youth, in Finland a lot of people have been empowered by her background.

Despite her young age, Marin has been brought in to steady the ship

Her socio-economical background is rare for the leader of a country. Marin has said that one of her biggest inspirations was the rock band Rage Against the Machine. “I have lived in a welfare state and am grateful for how society gave me support in the tough times of my life,” she repeated before her election on Sunday. She comes from a home with not much money, and was the first in her family to have a university degree. But it’s not just that. Rainbow families could feel empowered too, because Marin lived in a two-mum family. Some shared posts about how important it is for them show to be able to their children that our prime minister grew up in a family just like theirs.

Marin sounds like the perfect choice for any party that wants to modernise their image – and that might seem like a risk to many. Not in Finland. Despite her young age, Marin has been brought in to steady the ship, a prime minister determined to rebuild trust between members. She has promised to stick to the government’s programme. This means predictability. And she has no big interest in meddling with the trade unions, something that proved a problem for her predecessor.

But her age plays a part in uniting this coalition government too. Most of the party leaders are millennials, born in the 1980s. That makes communication easy. This unprecedented level of unity has led to some criticism, with people asking if the five parties have become too similar – based on their agenda, age and image. Of course, such “similarities” were never a problem when the majority of leaders were men.

And while her background may be inspiring, age certainly matters, for both Social Democrats and the Centre party. They are sliding in opinion polls, and their voters are more likely to be 70 than 30 years old. Both have lost supporters to the nationalist Finns party, which is currently leading the opinion polls, along with another opposition party, the centre-right National Coalition. Some social democrats worry that the rise of a young woman as prime minister might scare the rest of their middle-aged, not-so-liberal supporters away.

Finland anoints Sanna Marin, 34, as world's youngest serving prime minister Read more

This is certainly what the Finns party seems to expect. When Marin was elected, its leader Jussi Halla-aho tweeted congratulations – only to accompany it with a box of popcorn – to sarcastically indicate his joy at the calamity he believes will inevitable follow. As the Finns parliamentary group chairman Ville Tavio framed it on Facebook, it’s the culmination of a “modern feminist anti-male movement”.

The worry is that the gap between leftist-liberal and conservative-nationalist blocs will deepen. It is a polarisation that is seen throughout the world. The question is whether the record-breaking Marin government will be able to build trust between the generations, while also holding her party together. Or will this new prime minister only exacerbate the ongoing culture war between the two blocs?

• Tulikukka de Fresnes is political correspondent for the Finnish public broadcasting company YLE

• This article was amended on 17 December 2019. The subheading of an earlier version incorrectly implied that the Finnish people had elected Marin to the position of prime minister.