Jessica Graf, who is currently 11 weeks along, revealed her baby with fiancé Cody Nickson is due on April 11
Credit: Jessica Graf/Instagram

The Amazing Race winners Jessica Graf and Cody Nickson‘s next adventure will be … parenthood!

The engaged couple announced they are expecting their first child together on Instagram Monday, weeks after finding out in August.

“We actually found out while watching the finale of The Bachelorette. I wasn’t feeling well at all and decided to take a test even though I was pretty sure I wasn’t pregnant! I didn’t tell Cody I was taking a test,” Graf, 27, tells PEOPLE.

“I just went and laid back in bed with him, pregnancy test in my hoodie pocket. The show distracted me so I had forgotten it was in there until after it ended. I pulled the stick out and immediately gasped at the result!” the mother-to-be recalls.

Graf adds of Nickson, who is already a father to 6-year-old daughter Paisley, “Cody looked at me scared and confused at the look on my face when I handed him the stick! He immediately burst out into laughter and I burst into tears! It was the best surprise!”

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The couple first met during season 19 of Big Brother in late 2017, and announced their engagement in February.

“We don’t know the gender just yet! We are having a gender-reveal brunch the day after our wedding so that all our family and friends can celebrate with us. We weren’t trying to get pregnant … but we weren’t NOT trying,” she says.

“Our families are so excited! This will be my mom’s first grandchild and Cody’s parents’ eighth grandchild. Paisley, Cody’s daughter, has actually been asking us for a baby brother all summer. She spoke it into existence,” Graf jokes.

“As far as symptoms, I’m feeling great! My new superpower is my sense of smell. I can smell things miles away,” she adds to PEOPLE. “I don’t like to eat some of my favorite foods which are very weird but there hasn’t been any vomiting so I consider myself lucky!”

Jessica Graf and Cody Nickson
| Credit: GP/Star Max/GC Images

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On Monday, Graf shared the baby’s sonogram photo along with her pregnancy announcement.

“WE’RE PREGNANT! And I’m over the moon! I’m so excited to bring our first child into this life we have created together!” she wrote on Instagram. “I’m a little over 11 weeks and we plan on bringing our little angel into the world on April 11, 2019, just two days before Cody’s birthday. We’re honored to be adding the FIFTH Big Brother baby to the world! We can’t wait to meet you little one and we already love you more than anything!”

Nickson, 33, also posted the happy news on Instagram, writing, “Every day, Jessica and I thank the Lord for all the blessings He gives us. And now we are blessed with the greatest gift … a child. We are beyond pleased.”

“Thank you for all who have stood with us in support … and thank you to those who have opposed us to make all the victories worth it,” he continued. “I’m looking forward to Jessica being my wife and the matriarch of the Nickson establishment in Texas. What an incredible year.”