updated 06/20/2014 AT 11:00 PM ET
•originally published 06/21/2014 AT 9:20 AM ET
It was a day full of joyful preparation for a much-anticipated wedding – but it was also filled with prayer for a beloved mother not in attendance.
Jill Duggar, 23, the second daughter in the supersized Duggar family of TLC’s hit reality show 19 Kids & Counting, and fiancé Derick Dillard, 25, were surrounded by over 100 family and friends on Friday, helping prepare for their Saturday wedding.
Volunteers gathered to help with decorations, get food ready for the reception and help organize the church where over 2,000 guests are expected to watch Jill walk down the aisle – the first daughter of Jim Bob and Michelle to be married.
“I’ve been crying half the day, so I’m making jokes to keep from crying,” Jim Bob told everyone at the couple’s rehearsal dinner, where guests took turns sharing memories and advice for the couple.
During the rehearsal, Jim Bob and others asked those in attendance to pray for Dillard’s mother, Cathy, who is battling cancer and was unable to attend the rehearsal or dinner due to her health.
“I want to ask everyone to pray for my mom,” Dillard told PEOPLE. “Anyone who has been through [cancer] knows what it is like, and if everyone could think of her, I know she would really appreciate it.”
His younger brother, Daniel, will serve as his best man Saturday and told those in attendance: “I would like to speak for our mother and father and say we’re very proud of you, Derick, and know you will continue to make us proud.”
Surrounded by the entire Duggar clan – including eldest brother Josh, 25, and his wife Anna, 25, as well as their daughter, Mackynzie, 4, and sons Michael, 3, and Marcus, 1 – the couple still had much to celebrate.
After the rehearsal, guests dined on a barbecue buffet of brisket, chicken legs, baked beans, hash brown casserole and deviled eggs with an ice cream sundae station offering dessert.
Family and guests shared favorite stories of Jill and her husband-to-be, and the youngest Duggar kids, along with Michelle, gave them handcrafted pottery gifts they’d created especially for the occasion. Several of Jill’s younger siblings put together a movie reenactment of her engagement to Dillard that kept the audience laughing.
“We’re really, really excited,” Jill told PEOPLE. “My sisters have done a great job, and my wedding team of volunteers has gotten most of the wedding planning done ahead of time.”
“I try to tell her that it will be okay, everything will work out,” Dillard says.
One wedding present they’ve already received? Cereal. The couple admitted to adding it to their registry in a moment when hunger took over.
“We were hungry while we were making our registry and we gravitated over to the cereal section,” Dillard said, laughing. “We picked about five types of cereal, and we actually already got some.”