Jessie James Decker's heart is all filled up.

After all, the singer and her husband Eric Decker added one more to their family—with baby Denver joining siblings Vivianne, 9; Eric, 8; and Forrest, 5, last month.

"Having four kids is wild," Jessie exclusively told E! over email. "I never knew I would, but I love it. I love being a mom. It's just what I was born to do." 

As for how Denver's sister and brothers are adjusting to life with a baby in the house again?

"The big kids are super helpful," Jessie shared. "They'll do things like grab me a diaper or wipes. Vivi loves holding him while I'm cooking dinner. They love him so much and feel very protective of him."

While the Kittenish founder "felt very seasoned" going through the newborn phase for the fourth time, balancing life with a little one and three older kids isn't without hurdles. And her No. 1 teammate Eric has helped hold down the fort.

"The challenges have been just coordinating schedules," Jessie noted. "The three big kids are involved in a lot of sports and activities, and Eric is only one man! He's done an incredible job and, luckily, we have such an amazing community and family nearby to help with carpools, etc."

Another thing that's been helpful with balancing these busy schedules is saving time where she can.

"If there's one lesson I've learned, it's that food prepping is a lifesaver," the 35-year-old explained. "Whether for breakfast, after-school snacks or anything in between, having ready-to-grab options that my kids gravitate towards is a huge help." 

And that's why Jessie has partnered with Waterloo Sparkling Water to share some of her recipes—including a shrimp mango salad featuring the Tropical Fruit flavor or some mini muffins with the Summer Berry drink.

"Muffins have become one of my go-tos when food prepping," she admitted. "The kids love them before school or sports practices, and they last throughout the week. I incorporated Waterloo's delicious Summer Berry flavor into my muffin recipe, and they have been a hit."

And with the extra times she saves through meal prep, Jessie is savoring the quality time with her baby boy.

"Knowing this is my last baby, I'm definitely soaking it all in," the cookbook author shared. "I was really looking forward to breast-feeding again. It's one of my favorite things. I guess you could say feeding people is my love language."

She added, "It's especially special because I really didn't think we were having another one. Getting to do it all over again and have the newborn smells and kisses is so sweet."

Keep reading to see more of the Decker family's photos.

"Last Christmas as a family of 5 until baby brother is here," Jessie wrote on Instagram. "We love you already sweet boy."

The Decker's youngest, Forrest Decker, turned one in March of 2019 and of course they celebrated with balloons and kisses!

"Loves of my life #feelingrateful," Jessie James Decker captioned this sweet photo of her kids and her husband Eric Decker.

The Deckers visited Disneyland in February and despite trying to be romantic, the couple was photo-bombed by their son Eric Decker II. 

In January, the Decker boys cuddled up on the couch...dressed in their Woody pjs and watched some football.

On Christmas Eve, the Decker kids got into a little mischief, but we still think they're cute.

Come on, could these two be any cuter?

All three of the Decker kids including daughter Vivianne Decker, and sons Eric and Forrest were all smiles while out at the grocery store in November 2018.

We are loving all of these adorable costumes from Halloween 2018.

"My whole purpose in life #mifamilia," Jessie captioned this vacation snap from 2018.

What better way to celebrate 4th of July than hanging out on a boat with your sweet family?

Not everyone was happy to take this photo, but that didn't stop mom and dad from posting it.

In June, Eric became a human jungle gym thanks to his little kiddos.

Vivianne clearly loves her little brother Forrest in this precious pic from April 2018.

The former football player is always ready to hug it out with his little munchkins. 

Even though Jessie was sick in this photo, she had her two oldest kids to keep her spirits high.

In December 2017, the two oldest Decker kids had a big smile when they met Santa. 

Getting ready for Halloween is so much more fun when someone is wearing a Mickey Mouse head!

Aw, our hearts are so full looking at these two.

The country singer looked adorable as she waited to watch her husband's first game as a Tennessee Titan with her kids in August 2017.

The award for most patriotic family has to go to the Deckers.

Kisses and cuddles are what these two are best at and it's so freaking cute.

Vivianne got up on her dad's shoulders as the couple participated in a charity event in Tennessee in 2017.

"My wolf pack!" Jessie wrote alongside this photo of her family of four back in March 2017.

This party looks like a blast and we officially want to be invited to the next one.

Before the Deckers were a family of five they were hitting up weddings as a squad of four and looking good while doing it.

For Halloween in 2016, the fun family dressed up as characters from Peter Pan and they totally nailed it.

Ahead of Eric's 2016 season with the New York Jets, his family joined him at practice and we got this sweet photo as a souvenir. 

There's nothing quite like a family day at Disneyland.

Back in November 2015, the super mom and her two little ones enjoyed watching their main man dominate on the football field.