Hi Joe, Last year I was where you are now. Here’s my opinion.
First, find a GOOD Local Bike Shop. If you do, the rest is much easier. I started with an LBS that seemed to only be interested in making a sale. After talking on-line with other cyclists about what the LBS was telling me, I realized that they were not for me. The next LBS was interested in helping me find the right bike. They have been a great help this past year. So have all the on-line cyclists. Which brings me to the second thing - ask the on line experts here. You won’t go wrong.
Lastly - while I was shopping and before it got nice out I started climbing stairs at my office during my lunch hour. That helped build up my legs so I didn’t have as much trouble starting out.
Welcome and good luck. IMO cycling is a great way to add sparkle to your life.