I'm considering boxing (to the point that I bought the minimal equipment needed and visited a gym).
I have never been athletic (what I do is swimming by I never really disciplined myself to proper form, so I suck at it, and mountain biking, road bicycling and kayaking, but none of those are like the extreme kind), and I've also never had a fight. I'm the kind of person who flinched easily as a kid.
But I get to thinking one day, I bet that getting punched is one of those things that sounds scary until it actually happens, and then you're just over it. Like flying on a plane, which I had to do recently.
I molded my mouth guard today. It sucks getting used to it, but I've gotten a lot better over the day. Had to mold it twice. Hand wraps were easy to put on. The jump rope is a nightmare. I couldn't really try it in earnest because my legs were shredded from doing something else a day ago, but I know it's going to be hard. Considering holding off on going until I can at least keep a slow rhythm.
The gym is $100 a month, which sucks, but the most attractive alternative is an hour drive away and this one is literally a short walk from my apartment.
When I watched them I felt like my experience fencing (as a beginner, didn't stick around long) and square dancing helped. I never had much "physical intelligence," but square dancing has improved that dramatically. What mostly stood out was anatomy (like how people rotate into moves) and economy of motion. I think I understand the idea of it.
Edit: Square dancing with fluidity, understanding how other people move. It's almost all old geezers that square dance, I'm really out of place (and it does make me feel uncomfortable) there. Well, you learn how to lead people with things like spinning women. When these people are half-demented you learn to apply more pressure and make very expressive motions as clear signals to steer them towards doing the right thing. You know whether that geezer is going to be able to do a twirl in a swing, only swing, or not swing at all based on how old and doddering they are. Boxing is like this shit in reverse. One common sense thing that I had to discover was that bending your knees and moving your feet constantly makes you able to move more easily. See the boxers doing the same thing.