Currently I'm in a career change, as I have found something in the design/creative field. It's something I always wanted to do, but postponed for "career" reasons I pursued earlier.
At age 10 I wanted to go to a certain ivy league college, because I saw a documentary and the nature scenes looked so beautiful
. As I was pretty much quite stubborn and determined about this, I got there. After that things settled more or less.
I personally think the concept of re-defining yourself as no age limit. My mother is in her 70's and thinks about forming an NGO. Also something she wanted to do, but never implemented it properly.
It's never too late.