John Luke Robertson on his engagement to Mary Kate: People say we are too young but 'a lasting marriage does not depend on when you get married'

John Luke Robertson and Mary Kate McEacharn(Photo: John Luke Robertson)

John Luke Robertson is chuffed to bits to get his girl, Mary Kate McEacharn, after she accepted his proposal of marriage at the weekend.

He's already told Us Weekly that their shared faith in Jesus is a big part of their relationship.  In fact, he went as far as to say Mary Kate "never gave me the time of day until I started talking about Jesus".

And as much as he admits that his fiancĂ©e is "pretty good looking", he writes on his blog that what makes a marriage last is something much deeper than physical attraction.

"Some people say we are too young. I have heard all the stories and all the advice," he says.

"I have come to the conclusion that a lasting marriage does not depend on when you get married. A lasting marriage depends on how forgiving you are and how much you love God Almighty.  Those are the things that hold people together."

He and Mary Kate met at summer camp four years ago and they were later placed next to each other in chemistry class at school.

The Duck Dynasty clan and Mary Kate's parents are all "thrilled" by the engagement, even if John Luke did have to go through an "interrogation" from her dad to get his approval first!

John Luke's sister, Sadie, who is currently a contestant on Dancing With the Stars, told E! News she was excited to have her best friend marry her brother.

"I knew it was going to happen. Like I said, she's my best friend, and she's been my best friend since before they started dating, and I had knew it was coming, and I was super-excited!" Sadie said.

Mary Kate is also really happy to be walking into her new future with John Luke.  "I had always prayed God would bring a Christian boy into my life," she said.