1979 Kawasaki KZ650 C3

Ed, your second photo (from an FSM) is for the Kz400 twin. Your original photo is for a Kz400 inline-four (part of the 550 family).

Notice the motor cases are different, and the inline-four has the typical dual-cam head. The twin has a single cam. (You can tell by the shape of the valve cover, which I know Ed knows, but for anyone else reading this.)

Also, that twin has a rear drum whereas that inline-four has a rear disk.

You are absolutely correct! Sorry, I didn't even notice the last one was a twin. Ed

Its best to start out with a smaller bike, however don't be too afraid of a larger bike. My bike (83 kz1100) is my first. It weighs about 600 lbs. I'm only 5' 4" and about 130 lbs. It's lowered as low as it will go in stock form and I can just barely stand on my tippy toes. I can't even move the bike with me on it.
I chose this bike because it was in my budget (under 1k, I paid $800) I do wish I had a smaller bike sometimes, but its not that bad for me.
Just remember to take it easy when you first start riding on whatever you get. Originally I would get a little nervous on anything but pavement, now I hop curbs everyonce in awhile .

Good luck