The Jersey Shore starlet revealed her baby's sex in UsWeekly, saying she's "super excited and super emotional."
"I pictured a boy this whole time, so when I saw 'girl' on the paperwork, I was like, 'No way!'" she explained to the mag. "But deep down I think I knew!"
Of course, JWoww is excited that her best friend Snooki's son will have a baby BFF and for all of the girly milestones to come.
"She will be my best friend and daddy's little girl," Jenni, who's engaged to boyfriend Roger Mathews, says. "I can't wait for everything from her first steps to her first dance class."
But the MTV reality star and former wild child isn't so excited for her daughter's teenage years, which she assumes will be payback.
"I was a teenage girl once, and boy, do I know how sneaky we can be!" she laments. "Karma is gonna kick me in the butt with her!"
Congrats to Jenni and Roger!