I know this is a late response. I don’t know the answer but I do know that Joseph F. Smith, a future President of the LDS Church, served his first mission in Hawaii. He was only 15 years old when he started and served in Hawaii until he was 19 years old. There may have been other missionaries who were younger but that was the youngest person to serve I ever heard about.

JD,

We appreciate your visit. We are only a lay site and don’t have that information on hand. We recommend checking out the Historical Dept of The Church of Jesus Christ of Latter-day Saints.

Try this link: http://history.lds.org/?lang=eng and go to the Church History Catalog.

Thank you again for visiting the site!