Coaster brakes vs. Handle brakes i will be honest.  I am nearly 50y/o and not in tip top shape either. I have not owned a bike since I was 12y/o. I want to buy a bike. I am looking at the cruiser bikes.  Most come with coaster brakes.  I am not sure what to buy. I am new to biking, so I don't know.  I have heard more positives about handle brakes but also heard a lot of things could go wrong, and what if I get stranded somewhere? What would I do? Please advise.  Sorry if I am rambling.
There's a small chance you don't have as much hand/arm strength as you used to.  A coaster brake provides a way to slow while leaving your arms free to focus on steering.

That said, a coaster brake is a rear brake only.  The best stopping happens with the front brake, so ideally you'd have both, a coaster for the rear and a hand brake lever for the front.