I tried (a bit) but couldn’t find the source behind this quote:
Deciding what to do with the rest of your life in your early 20s is like deciding what you want for dinner before you’ve had breakfast…
Now when I am not in my 20s anymore, this makes perfect sense. I am guessing that I would have the same feeling after 10 years again. The feeling that I could’ve done things differently in my 30s. And on. So, one needn’t fret over past too much.