Chalk up one political victory for kids in Lower Manhattan.

Just as community and school officials were losing hope that Millennium High School would move to 75 Broad Street in September, Gov. George Pataki announced on April 24 that government money will ensure that the school gets its Downtown home.

But even after the governor’s speech, there were still doubts about whether the site can be ready by the start of the school year.

During a major speech on plans to rebuild Downtown, Pataki said that the Lower Manhattan Development Corporation will contribute up to $3 million for Millennium, and he called on the private sector to chip in as well.

The LMDC money, combined with funds that local elected officials had already committed and contributions from private sources, will pay to transform at least one floor of the office building at 75 Broad St. into a school.

“This takes away from all the guessing,” said Robert Rhodes, Millennium’s principal. “We’re very excited. It’s important for the school to have its own place.”

The new school opened last year with just a ninth-grade class in the High School for Art and Design building at Second Avenue and East 57th Street. But it was always slated to make its permanent home Downtown.

Preparing the new space by September will be a challenge. Late last month, lawyers were still negotiating a lease, architects had yet to be hired, and major construction lay ahead.

On April 28, a team of engineers, architects and representatives of the city’s School Construction Authority, School District 2 and Community Board 1 visited the site.

“They’re not sure the September opening is possible,” said Paul Hovitz, chair of CB1’s Youth and Education Committee. “It may happen, but everything needs to go perfectly.”

Roy Moskowitz, spokesman and counsel for District 2, said: “It’s fair to say that this is a tight schedule, but I have every belief that we will make it. The governor has spoken loud and clear that he wants the school up and running, and so do we.”

The plan, he said, calls for building only part of the school by September, when Millennium will be two grades; the school can move into more space later on. It wasn’t clear whether a gym, auditorium or other facilities aside from classrooms and offices will be ready by fall.

District 2 had applied for LMDC money last year. In recent months, CB1, education officials and local elected officials had urged the LMDC to make a commitment, while urgently seeking private funds. They said that money had to be secured by the end of this month for the school to have a shot at opening Downtown in September. But the LMDC put off a decision, until the governor’s announcement.

“I’m glad to see the governor follow suit,” said Councilman Alan Gerson, who committed $1 million in Council money for the school. Sheldon Silver, speaker of the State Assembly, and Assemblywoman Deborah Glick had promised a total of $2 million.

Nancy Poderycki, a spokeswoman for the LMDC, said the amount the agency provides will depend on how much money the school raises from private sources. “It depends on what the need is,” she said.

Battery Park City resident Rhonda Erb, whose son, Andrew, is a ninth grader at Millennium, and who heads the school’s parents’ association, said she had been confident the LMDC money would come through: “I thought it was just a matter of time. But I’m glad to see that they can start on some construction now.”