Age doesn't matter. Play fighting doesn't count. What counts is when there is genuine intent to physically harm on both sides. Boxing (in a ring) is a grey area imo. Let's not count it for the purposes of this poll. Ditto with supervised, organized martial-arts of any kind.
I've been in two.
I won both of them.
I was in my early teens, I think.
I did not start the fights,
and I had an awful feeling when I felt like I was gaining the advantage over the other person.
I was almost embarassed to say "zero" outside of fighting with my brother (like cats and dogs) but 010111 and PrplChknz make me feel better. Especialy Prpl - it takes couage to be that honest! Bravo!
I don't think that takes courage, its more fear if I was ever asked to prove my fighting skills if I said I had been in fights it'd be clear that I am not a fighter. I would say I'm a lover, but that's not true.