After years of observation, I don't think age has anything to do with marriage success. The best marriages I know--my parents (60 years married) and one of my best friends (30 years married)--were married at 18. While I certainly don't recommend that to my children, my daughter and her husband were married at only 21/22--after telling me at age 16 that she knew he was the one for her. We did everything to put them off because we thought they were "too young". They have been married now for 7 years, lost a child, and gone through some tough things, but I have witnessed their love for each other and seen how well they communicate. I have no doubt they will stay together.
I think marriage is all about maturity level (not age level), and commitment level. As a Mormon, I witness successful "young" marriages all of the time (aged 22-26 on average). When a couple is committed to fidelity before and after marriage, they are going to be more likely to marry younger and live more responsibly, as well as be more likely to treat each other with respect after marriage. Some people I have met in today's world wouldn't be mature enough for marriage at age 60.
Thank you for you time. Thank you for all you do for society, Dr. Laura, and for being a "voice for the children." We need more like you.