Congrats on your first ride! As someone who used to be 450 pounds (now 280) I can relate. I was sore all the time whether it was because of biking or walking something was sore. Stick with it, set realistic goals, and give yourself some spacer days to let your body recuperate.

Whatever you do, don't give up!

As for what to carry I think most everyone covered it ... tire, levers, repair kit, id, tool perhaps, pump, and some cash.

Have fun out there!