Fist you have to decide what your goals are. Do you want to compete or just get in shape and learn? Have you gone to the gym and talked with the head instructors? I would go to the gym watch some of their session (if they let you, which I don’t see any reason they wouldn’t if you wanted to join). Also see how they teach. Any instructor can break a student. Are they trying to help build their guys? Also you seem like a big guy. Do they have other big guys that train? This will help you during the grappling and clinch. If all they have is smaller guys, when you start learning the techniques this will not help you.
Everyone has to start somewhere. Yea you can try to keep losing weight, but just lifting weights is different than sparring and grappling. Also ask questions of the instructors. How long have they been training, what kind of equipment they have/use, how many times they want you training, etc.
As for the clothing/gloves, again you have to talk with the instructor. Some have gloves students can borrow until they get their own, but my guess is you will have to get your own eventually.
Sorry for how long this reply was.