I'm really glad to have a chance to come back to this thread...
While I know some people just sort of decided what they're going to be when they grow up, go to school, do that, and live happily ever after... That simply hasn't been my experience with life. LOL. Nor most of the normal/not-PTSD people I know. Even disincluding the tap dancing astronaut ninja phase most kids go through (Or as the comedian Russell says about the UK introducing career counseling to 7yos program "What do you want to be when you grow up?" / -pause- "Dragon.") , most of my normal friends / family have made at least a couple wild changes in direction in their lives.
Myself? While I took the question literally (while I'd planned on a military career and PTSD tanked that) the first go round...coming back to this question in a different headspace, I'm really looking at all of the abrupt 180s my life has taken, both before PTSD and after.
Things I almost was could practically be a novel.
I've actually worked dozens of jobs in wildly disparate fields (most legal, but a few quasi legal at best, down to a couple outright illegal). Ironically the outright illegal ones ended up meaning I had an open invitation to be a LEO/sworn officer in a particular sheriff's department. I mean, that's just backwards, but it also my life. Even more "my life": Had an invitation -past tense- for over a decade, because as soon as I decided "Okay. We'll do that, then." The Sheriff got pancreatic cancer and passed in less than a month. Okay. Not that, then. f*ck...
Even that list isn't complete, because it's not including things I wanted to do (when I say 'Run away and join the circus' I'm not using a metaphor... I was a competitive athlete, before I got all broken down and knackered it was an actual wish, now it's an "I want to be fixed and then run away and join the circus), or worse things I've actually put quite a bit of time and energy into that I've either found out I'm crap at, or even my New Category; Things my stalker has kept me from doing (Whee!). Seriously. I need a new name and social security number and PO box. This is my mission for the next couple months.
If I can climb out of my depression long enough to maybe, actually, do it.
Forehead. Drywall. Repeat.