My only reasoning was that I was the youngest of 4 kids and I wanted to do something different than my older siblings who had all gone to BYU. My parents told me I could go wherever I wanted after my mission.
About 18 months into my mission I realized what my social life and spiritual life would be like at Colorado University where many of my friends from highschool went- few lds girls to date- all the parties that just devolve into drunken stupidity (I attended plenty of those in high school and as a non-drinker they are extremely boring. I was always amazed at how my friends raved about the awesome party was on the following Monday that was actually really dumb and boring)
Anyway- teenager’s choices shouldn’t surprise anyone.