Jessie James Decker Shares Sweet Photo of Her 16-Week Baby Bump on Instagram

On Friday, Jessie James Decker shared a sweet photo of her growing baby bump on social media.

“Sixteen weeks today,” the country-pop singer wrote alongside a photo of her visible baby bump. “Where are all my mamas?”

In an exclusive sit-down with PEOPLE on Monday, Jessie revealed that her daughter Vivianne “Vivi” Rose, 3½, had a big part in the story behind her and Eric Decker‘s third child on the way.

“We knew that we possibly wanted a third [child], but I remember she pulled me aside — one of our friends had a baby, and [Vivianne] is really close with their child already, they’re the same age. … His name’s Henley, and Henley just had a baby sister,” explained Jessie, 29.

16 weeks today ?????? where are all my mamas?

A post shared by Jessie James Decker (@jessiejamesdecker) on Oct 20, 2017 at 11:58am PDT

“My son, [Eric Thomas II “Bubby”], is 2, so she doesn’t remember him ever being a baby, they’re 17 months apart,” she added. “So she’s like, ‘Mommy, I want a baby sister like Ellie, I want a baby sister.’ I was like, ‘Well, if you really want a baby brother or sister, you have to pray to Jesus.’ ”

“So every night I would hear her going, ‘Jesus, please help have a brother or sister,’ ” Jessie recalled. “She would just pray. And then my mom, who’s super Catholic, pulls out the rosary. So [Vivianne] pulled out the rosary and she’s 3, going, ‘I want a baby sister!’ ”

Eric Decker (left) with Vivianne, Eric Thomas II and Jessie James Decker
Eric Decker (left) with Vivianne, Eric Thomas II and Jessie James Decker

The couple — who star in the E! reality series Eric & Jessie: Game On — chronicled their decision to try for another child on an episode of the show. And Jessie told PEOPLE that while she came from a larger family, her NFL star husband didn’t — and she wanted him to have that experience he craved.

“I just felt and feel so fulfilled with our two I didn’t really think about it — like, I’m not longing for another child,” she explained. “I just feel like we’ve got it going on with Vivi and Bubby.”

“But I think because I came from a family of three siblings, I know what that’s like, and it was great, and Eric came from a family of just him and his sister,” she continued. “He wants to experience that whole big family process, so I’m not gonna take that away from him.”