Meh nobody plans on living after x age anymore. Good thing is, when you get closer to said age, you won't pay attention, and eventually you've already forgotten what you thought about it earlier 
I remember thinking when I turned 30 (yes, I still remember it, yay!), that some sort of 30s-crisis should hit me. -- I think midlife crisis is around your 40s to 50s -- . Anyway, nothing much happened at first. I did realize though, that most of my friends had gotten married, were just then having their first or second kids, really settled down at all. And there I was, travelling between the UK and Finland, working towards getting a total burnout at work, etc. (Goal achieved soon after).
Instead of wanting to have kids or get hitched, I decided to buy a house on my own. I did, and don't regret it, sold it later with some profit, as I made lots of renovations in it at the time. I got weird looks from friends, who were asking why am I buying a whole big house just for myself, with no family? Yep, that was a bit insulting, I felt, and kept replying that i don't need a man or a family to do this by myself, for myself, if I was able to do it on my own. 
So, I guess i had some feeling of anchoring myself somewhere for a few years kind of a 30s-crisis there. Glad I wasn't buying a midlife-crisis-Harley or a sportscar
... got that stuff dealt with later, when then moved elsewhere and lived with a MCC guy for some years.
Just trying to say that 30s crisis or midlife crisis isn't necessarily a bad thing. It can push you to do something that you may have wanted to do for a long time but just didn't get around to it or just needed some extra incentive for it.
Hell, one of those friends of mine, who was having a kid right then when I turned 30, faced her similar crisis some years later.. and decided to go back to the Uni to study a new profession.
And another gave up his lucrative management level job at an IT company, after being fed up with the work stress bullshite, moved far up north, and started to grow huskies and a dog safari company with an uncertain future.