Congrats to state Sen. Andrea Stewart-Cousins, who come January will be the first woman ever to run a chamber of New York’s Legislature.

The voters this month

gave Democrats commanding control

of the state Senate, 40 to 23, and on Monday her Democratic colleagues re-elected her as conference leader.

She’ll join Assembly Speaker Carl Heastie to mark the first time African-Americans lead both of New York’s legislative chambers.

So next year will bring a different-looking “three men in a room” hashing out pretty much every major piece of legislation behind closed doors. As to whether the process will be all that different, or less rancid, well . . . we’ll see.

As Democratic leader since 2013, Stewart-Cousins has a decent track record when it comes to condemning Albany’s secretive deal-making. Maybe she’ll see it the same way now that she’s not being shut out of the secret deals.

With a district that covers much of West­chester, including Yonkers, the Senate’s new chief is long used to representing a diverse constituency. As The Wall Street Journal reports, she’s known as “an attentive listener who is deliberative and patient but clear and firm in her positions.”

She’ll need those skills to run a conference that just got markedly more diverse even as it grew, adding not just the left-leaning rebels who ousted most members of the old Independent Democratic Conference, but also a pack of suburban moderates who defeated actual Republicans.

Can she handle that balancing act while also pushing to open up the legislative process? At least one colleague thinks so: State Sen. Shelley Mayer (D-Port Chester) says, “I have incredible faith in Andrea’s integrity and her passion [for] doing the right thing.”

Mayer argues that the recent corruption convictions of so many legislators, plus Stewart-Cousins’ rise, means that “we’re embarking on a new day.”

Cross your fingers that it’s so.