As for the stage fright, it never goes away. When I'm waiting in the wings to go on, it's agony every single time but I stay focused and I know that once I'm on stage it'll be fine; I'll be in my happy little bubble.
You have actors who begin at a certain young age and there's very little change in their technique and the depth of their performances; they're the same 30 years later.
All sport... is one of the few activities where young people can proceed along traditional avenues, where objectives are clear, where the desire to win is not only permissible, but encouraged.