While most 18-year-old boys are more interested in dating several women at once rather than marrying one, Josiah Duggar is already planning to settle down.

The teen announced Monday that he and Marjorie Jackson, 17, began courting on April 6.

Duggar and Jackson began as friends, and their feelings blossomed into a relationship.

"I met Marjorie a few years ago, when I was taking Spanish lessons at her house and I was very impressed with the way she was with her siblings and her love for the Lord," Duggar told PEOPLE.

Jackson, the daughter of Greg and Analucia, has four sisters. She said the initial interest was mutual.

"I met him at Spanish class a few years back," she confirmed. "For me it was an immediate thing. I have always admired him and his family."

Their feelings increased after the teens went on a mission trip to El Salvador in December.

"She really caught my eye," Duggar admitted. "That is really where I noticed her."

The couple's courtship began on the same day that Josiah's sister, Jill Dillard, gave birth to her firstborn son, Israel David. Jill and husband, Derick, will celebrate their one-year wedding anniversary on June 21.

The eldest Duggar, Josh, has three children with his wife, Anna, and they are currently expecting a fourth child. Jessa Duggar, 22, married Ben Seewald on November 1, but there have been no pregnancy announcements to date.

The eldest Duggar daughter, Jana, has consistently shot down rumours of a relationship with former NFL star Tim Tebow, and has not publicly been in a courting relationship.

Parents Jim Bob and Michelle Duggar have not had any babies of their own since Josie was born prematurely in 2009. The couple suffered a miscarriage in 2011 but seem to be relishing being grandparents to their children's children, including latest addition Jill and Derick's baby, Israel David.