Morning Rhonda
In part, I tend to think it's part anxiety and hormonal related. I say this because of my own experience. When I hit about 42 and my Estrogen began to drop, my anxiety/nervousness went up and I became more cautious and of all things, Claustrophobic, I tried hypnosis, talk therapy and even EFT. All had some merit, but not enough to cure me.. Then I began to read up on Perimenopause... Turns out, as Estrogen lowers, our Cortisol rises (stress hormone) ... Estrogen is what controls the cortisol centers.. I now believe that with my hormones shifting, I began to become more nervous and with that more CAUTIOUS...However, now that I have a better understanding of what the heck is going on with my hormones (particularly on each day of the month ) as I track my cycle on paper.. I can now get back (somewhat) to my old self.. the person like you, who had a lot of guts and would go out and explore life...
I know my explanation sounds clinical... but I truly believe many women in their late 30s , 40 and even 50s are experiencing what you describe.. and sadly, our doctors just think we are going through mid-life crisis..
I do think that yes, I became more brave about some things.. but it's those little things (like leaving an airport) that would become a big issue for me.. in my case, even riding public transportation was becoming tough because I didn't like to be boxed in ...
There's a book I recommend that helped me a lot.... called, Screaming to be heard.. by Elizabeth Vliet..
Her book was so much more helpful to me than any mainstream or alternative doctor I had ever seen.. since learning more in depth about what's going on inside me.. I feel that I can take my life and live it not on the edge but at least with more zeal... and the bravado that you speak of... that too is making its way around for me again..
I wish you all the best