Hailey Baldwin's Going to Be an Aunt! Sister Alaia Baldwin Expecting First Child, a Baby Girl

Hailey Baldwin is going to be an aunt!

The model’s older sister, Alaia Baldwin, announced on Friday that she is expecting her first child with husband Andrew Aronow.

“I made something extra special for @andrewaronow’s birthday this year,” Alaia, 27, captioned a sweet Instagram photo of Aronow kissing her growing baby bump, adding that the baby girl is due in August.

Clearly overflowing with joy over the happy news, Hailey, 23, commented on the post, writing “My niece” and “Screaming!!!!” before sharing the photo to her own Instagram Story.

“I’m gonna be an Aunty!!!!!!!” she exclaimed.

Never miss a story — sign up for PEOPLE’s free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories

RELATED: Justin Bieber and Hailey Baldwin Share Cuddles and an Easter Feast to Mark Holiday in Canada: ‘Love U Babe’

As for starting her own family, both Hailey and her husband Justin Bieber have said they want to wait a bit before taking that next step.

“I love kids and I can’t wait to have my own,” she told Vogue Arabia in December 2018, two months after tying the knot with Bieber, 26. “I would say that now, that’s a closer reality, but definitely not anytime soon.”

Echoing the same sentiment, the Canadian pop star recently told Apple Music’s Zane Lowe that while he does want children, now is not the time.

“I want to start my own family in due time,” the “Yummy” singer said in February. “I want to enjoy being married for a little bit, go on tour, be married, enjoy traveling with just us, build more of our relationship. I think that it’s definitely the next step, for sure.”

RELATED: Justin Bieber Wants the ‘Holy Spirit’ to Lead Him in Fatherhood: ‘I’m a Jesus Follower’

And when it comes to just how many children the couple see in their future, Bieber has said he’ll let Baldwin take the lead on those decisions.

I think it’s up to Hailey because it’s her body,” Bieber said during an appearance on The Ellen DeGeneres Show in early March. responded, earning huge cheers from the audience.

The couple tied wed in New York City courthouse in September 2018, just two months after getting engaged, and celebrated with a larger ceremony in front of family and friends a year later.