I bought a Road King Classic as a first bike and didn't die. I'm pretty much Superman though, so there's that. Average humans shouldn't try to do the things I do, because I'm pretty special.
Get an inexpensive, cruiser type bike from Craigslist and ride it for the summer. While your learning and gaining experience you can narrow down the model of Harley you want.
I would suggest that 45 is too late in life to start riding a motorcycle. But I have been wrong in my life many times.
You are way wrong, my wife started at 53, having NEVER ridden bike before after taking proper training her FIRST bike was a 2009 HD Deluxe, she is a great rider, better than a lot of her friends who have been riding many years!
Of Course, I have to say "riding a bike safely dwn the street hardly makes one a safe".
In fact, being able to do backflips through the air is not the trick needed to ride dwn the street!