Welcome ‘freak,
…from a fellow clydesdale. I have come from teetering around that 300# mark to just over 200# and feel great now. Congrats on your recent reduction. Just stay active and you will continue to feel good. Biking is a fantastic way to stay active and thus, fit.
The only thing I would add to what the others have said is to make sure you have comfortable riding apparel. Some guys ride comfortably all day in T-shirts and gym shorts. I have always had a problem with "saddle soreness" until recently when I tried padded bike shorts. It made a world of difference in my comfort level especially on extended rides. Don’t know if or not you’ll experience a problem, but if you should, you’ll know that there is something you can try that may help to keep you riding. A sweat wicking jersey is also a "plus" for comfort, if you get tired of the sopping T-shirt thing.
The most important thing is that you get out there and do it, no matter what for a ride or gear you have. As you ride, you’ll discover what upgrades you need or would like. That’s part of the fun. Speaking of FUN; have lots of it!!!!
gw