I’d say get reasonably slim and generally fit; and then pursue martial arts.
Run, swim, lift weights, do callisthenics, climb, dive, surf, skate, chase girls etc.
Let me explain:
You say you’re obese. That means you’re very fat.
Congrats on being frank. Most people never manage to get to that point, much less past it.
It is difficult but entirely possible today to get the body you want, within certain genetic limitations of course. Luckily it’s easier for men then for women to get strong and fast.
But it can be hard to do multiple things at one time.
Especially when you’re/were fat AND untrained AND decide to shred pounds, getting into highly a technical sport (MA) is really less then optimal.
you will get suboptimal weightloss results,
you will improve only slowly in the sport, if at all, since your body is (hopefully) drastically changing at the same time
your chance of injuring yourself goes dramatically up (you’re overweight and most martial arts can be fairly destructive)
you will plateau with your weightloss a lot harder, and a breakthrough will be probably impossible without some close coach who really knows his shit
Shed the weight first.
Post pics and a detailed background in the other forums, follow the lead of the veterans there and report back when the job’s done.