So what's this new addition to the family like?
When the newly engaged couple – whose courtship will be featured in the new season of TLC's hit reality show 19 Kids & Counting kicking off Sept. 2 at 9 p.m. – first started their relationship, Seewald's parents, Michael and Guinn, shared insights about their son, 19, and his relationship with Jessa, 21.
"When Michael and I had Ben, he was a great baby, but he was a real handful as a toddler," Guinn, 40, told PEOPLE. "He was very adventurous. He was a very opinionated kid."
Ben, who is the oldest of seven children and lives in Hot Springs, Arkansas, is a sophomore in college majoring in political science .
"He is mature and always has been," his father, Michael, 39, said. "We have tried to treat him like an adult growing up. He did kid things, but with adulthood in view. He has had that his whole life."
As the first of their children to enter into a "courtship" – a more serious relationship than traditional dating, with marriage as its goal – his parents say they have tried to give him a good foundation for becoming a good husband and father someday.
"He is ... doing well," Guinn said. "He is handling a full plate right now."
In their courtship before becoming engaged, Jessa and Ben decided to wait to hold hands until their engagement and save their first kiss until their wedding day, as Jessa's older sister Jill did when she married Derick Dillard.
"There is nothing in the Bible that says 'thou shalt court,' " Guinn said. "But we have raised our kids to know that someone else's heart is like a treasure, and you want to be careful with that other person and treat them with great respect. There is no perfect pattern. Treat other people as a gift. Honor God and your relationship."
Bribing with SkittlesWhen courting couples go out together, a chaperone goes along, and Ben shared that getting one of his new fiancée's younger siblings to agree to chaperone isn't always easy.
"Jessa and I found out that Jill and Derick were bribing the younger Duggar kids with Skittles payment to be chaperones for them," Ben told PEOPLE this summer. "We had no idea that's why they had such an easier time of getting chaperones."
Though Ben's parents have fewer kids than Jim Bob, 48, and Michelle, 47, they say that Jessa and Ben's decisions about parenthood are up to the young couple themselves.
"How many kids they have is Ben and Jessa's decision, and they can figure that out," Michael said.
And though their son is young, both his parents say he's mature enough to handle this relationship.
"I was the same age as Ben when I was going through the same thing," Michael said. "For me, it helped to mature me. A committed relationship does a lot to mature a young man. It does make them grow up a little bit. I can see that happening to Ben already."
And how do Jessa's new in-laws-to-be feel about their new future daughter-in-law?
"She is very strong," Guinn said. "She is very intelligent. She has a lot to offer to a conversation. She has great ideas – I have enjoyed getting to know her."
Michael agrees: "She is exactly who we would want our son to have a relationship with."