If I read your post correctly Ranger1, your main worry seems to be that they have known their prospective new spouses for a very short time.
It doesn't always take very long to establish a relationship, and the old adage "marry in haste, repent at leisure" usually applies to young people with little or no experience of what is required for a successful marriage. Remember that your parents are not looking into a sixty or seventy year future any more.
I met my wife on a Saturday evening, and proposed on the Sunday. She said yes, and in April 2005 we celebrated our 40th anniversary with our two chidren, their spouses, three grandchildren, my parents, and my wife's mother. I've never had the inclination to repent, hell, I've never had the TIME.