I blame this kind of thinking for the divorce rate. You cannot successfully grow old with someone you don't know and you don't know a person, at least not enough to decide you want to spend the rest of your life with them, for years and years. Also, both parties need to be adults before the "deciding to spend the rest of your lives together" part occurs. And growing up can happen when you're 15 or 40.
And you, Dave are most certainly not a grown up yet.
(But it's okay! Neither am I.)