Hearty Cycler

Hello everyone,
I just introduced myself in the 50+ thread, then received an invitation from Brian to introduce myself here, so I hope I'm not breaking any forum rules by plagiarizing from myself and in effect, double posting.

I'm 56 y.o., a quadruple bypass veteran (3 years ago), in pretty decent shape now thanks to regular exercising and good nutrition, and I haven't really ridden a bike in 35 or so years.

When I was a kid, I rode my one speed, heavyweight, tubular tired bike everywhere. Always believed that the bike skills that I learned as a kid were always going to be a part of me. Last year, I got into a conversation with a 59 y.o. acquaintance/friend of mine about how I was thinking about getting a bike and wanted to ride again. Unknown to me, he had returned to cycling about 6 years ago, and said that there was no time like the present. He had two bikes, I got on one, and we rode along a perfectly flat road (we were at the beach) 2.5 miles with the wind and 2.5 miles into the wind on our return trip. The trip was a bit uncomfortable, yet fun, but I noticed that my bike riding skills were all but gone.

I expected the trip to be difficult from a workout/fitness perspective. I hadn't realized that the feel of a bike would seem so foreign to me. It was towards the end of the season, and that turned out to be the only ride that I took last year.

I've spent this past year reading about and researching bikes and wound up buying a used bike from a good friend of my brother. It's a Cannondale T2000, in near new condition. It's an XL size, suitable for my 6'3" frame. I also loved the fact that it's a 27 speed bike with very low gears. I took it to my LBS and had them check the fit. They also talked me into clipless pedals.

The weather is just starting to turn nice now here in the Northeast, and I took my first trip on it two days ago. I was planning on riding 4-5 miles, but was gassed after only 2 miles. Also found the clipless
pedals a bit tricky along with riding on a real road with rolling hills and not being able to shift intuitively. I was exhausted from all of the thinking that I had to do while also realizing that, although in good shape, apparently I'm not in bike shape. Planning on going out again today. I've got a long way to go, I know, but was wondering how long you guys think it will take for my riding to even begin to feel reasonably normal.

I'm looking forward to being a member of this community and hope that I'll be able to (eventually) contribute to it. I'm open to any advice that you may have me, and look forward to hanging here.
Cheers!