Jim Bob and Michelle's oldest child is about to start a family of his own

Credit: TLC

Looks like there’s not going to be a shortage of Duggars anytime soon.

Joshua, 21 – the oldest of 18 kids born to Jim Bob and Michelle Duggar of Tontitown, Ark. – and his wife, Anna, 20, are expecting a baby of their own.

“I am very excited and am learning new ways every day that I can be there for my wife,” Joshua tells PEOPLE. “I thought that she would be the only one going through the emotions of pregnancy, but I’m right there with her.”

So “right there” that it was actually Joshua who gave Anna the big news.

‘So Thrilled’

“I took the pregnancy test, but I couldn’t bear to look at it because I didn’t want to be disappointed,” Anna explains. Joshua managed to keep the positive test a secret and announced it to the whole Duggar family, including Anna, later that night. “I said, ‘You’re going to join the Mommy team,’ ” Joshua says.

The giant J-named Duggar crew (all 18 children have names beginning with that letter) is featured in this week’s issue of PEOPLE, sharing how they live debt-free and keep order amid the chaos of family life.

“We are so thrilled about this news,” Michelle says. “It is so fun to be around Josh and Anna. They are walking on clouds.” Jim Bob agrees: “We are really excited about being grandparents. We think it is really going to be easier than being parents.” The couple’s pregnancy will be featured on the TLC show about the clan, 18 Kids and Counting.

Advice from Mother-in-Law

Joshua and Anna live near the rest of the family and run their own car dealership in Springdale, Ark., and Anna says she is taking advantage of her mother-in-law’s experience in the pregnancy department: “She told me to eat small meals frequently during the day to get through the morning sickness,” she says. “And she gave me apricot juice that I’ve been sipping. It really helps a lot.”

Joshua and Anna, who married in September 2008, are getting ready for the baby, due in October, by reading through pregnancy materials from Dr. Amy Sarver (the same ob-gyn who delivered the last three Duggar babies) and contemplating baby names.

Names beginning with the letter J?

“Discussions are underway,” Joshua says. “We are planning on a name theme, but we are not sure what it will be.”

“If they have a boy, they’re welcome to name him Jim Bob,” says Jim Bob, laughing. The couple’s happy news was first reported on Monday’s Today show.

For more on the Duggars, pick up the latest PEOPLE, on newsstands now