Better hurry, there J.
I was feeling in a rather flippant mood, and was going to answer something a bit wrong, but thought better of it. In reality, I swing back and forth on this topic quite a bit. I don't feel that it is a particular individual age, rather an age of a particular individual. My sister got married when she was 19, I am (somewhat) older than that now, being the big brother and having over 10 years go by since then, and am in no position to start to think about that at all. But she and her husband are going as strong as ever (6 kids! We joke about getting them separate beds for Christmas...).
As for me, well, they say once bitten twice shy, and my history is filled with teethmarks. Never quite to the aisle, but close enough. And I am incredibly grateful that each of the girls in question did not end up as my wife (for some good reasons, for others as well). They weren't ready, nor was I. I don't think I am now, either. And I certainly couldn't have my current life if I was married, and that is something I am very grateful for (as, I hope, are a few others...)