“I was the first person to know, obviously besides Rob [Kardashian],” Rose tells PEOPLE exclusively of her best friend spilling the beans earlier this year. “I wanted to shout it out to the world like this is my baby, but I couldn’t.”
In the moment, “I was screaming and like ‘Oh my God we’re having a baby!’ ” she says. “Chyna’s my family so if she’s having a baby, I’m having a baby.”
It’s much-needed support for the young mom, 28, who sources say is still largely on the outs with her future in-laws.
“The family still feels that Rob’s relationship with Blac Chyna is rushed,” a source told PEOPLE this week. Despite Rose holding her tongue, a rep for Chyna told PEOPLE that the couple’s baby news was allegedly leaked prematurely by a member of Kardashian’s family, seemingly to promote their show.
RELATED VIDEO: Rob Kardashian and Blac Chyna Make First Appearance Since Announcing Baby News
Still, says Rose, 32, the mom and pregnant bride-to-be couldn’t be happier.
“She’s ecstatic. She’s pregnant and she’s with a man that they’re both deeply in love with each other,” Rose says. “To be happy and in love and having a baby and getting married. It’s a great situation to be in.”
“We’ve got some time for sure,” she says of the couple’s pending nuptials.
And though Chyna – who’s been busy with the launch of her CHYmoji app – was by her side at last year’s SlutWalk, Rose says, her pal’s got a great excuse to sit this one out.
“She’s going to probably be around 9 months then,” says Rose of the event in Los Angeles on Oct. 1, suggesting Chyna is currently around four months pregnant. “It depends on how she feels. I know she supports me no matter what, but it’s going to be hot! I would hate for her to be out there at 9 months!”