Blac Chyna Car Crash ... Reality Star is Hit and Run Culprit

Blac Chyna was telling the truth when she said she wasn't behind the wheel during a hit and run crash earlier this month ... we've learned, the driver's a reality TV star, and she's in big trouble.

TMZ broke the story ... Chyna's white BMW nailed another vehicle carrying 3 passengers in the valley. Witnesses say two African-American women in mini skirts bailed from the Beamer and Chyna remained adamant, it wasn't her.

Now, sources close to the investigation are backing BC up. We're told Paige Addison from the show "Boss Nails" met with the LAPD earlier this week with her attorney and admitted she was the driver.

We're told Paige told cops Blac Chyna was not in the car and not at the crash scene.

Law enforcement sources say the case will be referred to prosecutors ... leaving the scene of an accident where there are injuries can be prosecuted as a felony.

We reached out to Paige ... so far, no word back.