The answer is a really really harsh reality:

Life is a race against yourself because many many people don't make it out of their 20s. Either literally by death or by dying while alive.

I'm 30 so I feel like I'm just exiting this phase. I've known 2 people who died unexpectedly through no fault of their own. One was 19 the other 23.

I know countless others who will never get the chance at a normal/typical/ full life after their 20s. Just a few examples

• 23ish playing soccer, friend jumped too high and fell on another player, wrecked his back so severely he is basically paralyzed.
• 31 chose his job over his potential spouse, last few years he's turned into an alcoholic and shell of a person. Could turn it around, but I doubt It.
• 22 one of the smartest girls I knew, drove drunk with friends and died. 3 people dead.

And those are just the ones that immediately sprang to mind. So I think the reality is this, Vienna waits for you if you don't fuck it up or die by accident. And lots of people do one or the other.