Student mum Sian Bruce, aged 17, has been at the school for a year while caring for 9-month-old Te Matahauariki Bedggood.
"I love this school I don't want to leave. Without it I don't know where I would be," she said.
She aims to get NCEA and then enrol in a tourism course.
Lou and Sharon Davis first started the school more than 10 years ago in a room at the Raumanga Uniting Church. Since then it has moved locations and been run by different people. Now there are 17 similar schools around the country.
In an Education Review Office report in 2009 the school was praised for its academic record but was slammed for its poor quality premises.
They had to put up with a leaking roof, asbestos in the ceiling, inadequate toilet and kitchen facilities, and a complete lack of hot water.
A few weeks ago hundreds of banana boxes were packed up from the three former primary-school classrooms leased from community organisation Te Ora Hou just down the hill and unpacked in the new building.
School statutory manager Derek Birt, who has been dealing with the school's complicated property issues for four years, said securing funds for the upgrade had been his main goal.
Mr Birt works with the board of He Mataariki's host school, Mangakahia Area School.
School manager Terri Cunningham said the new school would enhance the learning journey for the young mums.
She said students who had been to school had gone onto higher education including one mum who had completed a teaching degree and had secured a job in Ahipara.
Val Cooper, wife of the late John Cooper who was the building architect, said her husband would have been so proud to have seen the school finished. It was his last design before he passed away.
Mrs Cooper wished all the school's students all the best for the future.
"A good education will stand you in good stead for the rest of your life. Make the most of the opportunities offered to you in this building," Mrs Cooper said.
