My grandparents got married at a very young age and a lot of what I think about marriage is based on their relationship. I watched them over the years and saw how they dealt with everything together as a team.
What I think is amazing is not that 85% of people who get married under the age of 25 get divorced it's that 15% of them stay together. How did they manage to pull that off? You almost can't wait too long. It's the single simplest measure to predict divorce.