I think this may be my first post in this forum, but your situation is very similar to what mine was a few months ago. I started riding again at age 59, after 14 years off the bike, and 70+ pounds heavier than when I used to ride a road bike. I'm now down about 45 of those pounds, working on losing the remaining 30 that I gained over the years, and I'll tell you that the bike I'd be interested in now is very different from the one I needed 6 months ago.

We have a bunch of things that happen to us (or at least to some of us) as we get older: we get fatter, which makes being hunched over in an aggressive riding position really uncomfortable - for me, it actually interfered with breathing. We develop orthopedic issues - arthritis, stenosis, poorly resolved injuries, etc. These may impact the positions we'll be comfortable with. And then, if you're male, there are the issues around what happens when you're taking a pounding in the perineum. (I dunno about you, but I'm not done with that stuff, and don't want to risk anything that could interfere with its remaining function...) And finally, if you've been a couch potato for many years, there's the issue of core strength (or the lack of it.)

Some of these conditions start to improve as you lose weight and get into better shape. Others of them you might just be stuck with. What I needed six months ago was a very upright ride and a sprung saddle. I used an old rigid frame mountain bike that I had, and extended the quill, changed out the bars, and used a seat with springs - all to give me an upright ride without pounding the heck out of my nether regions.

Now, I like a different bike. I can get down lower, and fully upright is annoying. And I'm stronger, so I worry more about chafing from a wide, springy seat than I worry about not being able to absorb the bumps in my legs and middle. But I still have issues with arthritis and stenosis in my neck, so a very aggressive riding position is still out for me. Now, a compromise works better.

What this might argue for is getting something second-hand pretty cheap, and customizing it to get you through that first six months. An older mountain bike (without all the suspension stuff), or a decent quality older hybrid could be just the thing. Even an older road bike that you can put riser bars and a different stem on would do the trick.

In six months, after you've lost some of the extra weight and gotten in better shape, you will see what kind of ride you want, and you can get what you need then. I think its always a work in progress, especially at our age - our needs and requirements change pretty quickly. Besides, tinkering with bikes is fun!