If there is a difference in the rate of divorce from people who marry young, I think it is because the majority of young people are likely to believe in the fairy tale of marriage. They have little experience managing a household on their own. Their money management skills may be lacking. Someone who is 19 or 20 hasn't quite discovered what they want to do with life yet and that can be difficult to go through with another person. The spouse may not be understanding or may be going through the same dilemmas as well.
However, there are mature young people who have lived on their own and have experiences with married couples that may show them some of the reality of married life day to day. On the other hand, someone who is 35 when she gets married is more likely to have her own place and is used to dealing with money, had goals in life, may have accomplished some, and is just more settled overall.
I still think that morals, maturity, values, and committment will determine your success in marriage more than any other factors.
For the record, I'm happily married.
