I would spend a few hundred more and get a bike less than 10 years old, unless you are a mechanic or have a special deal with a mechanic friend. If you buy an old bike, it is best to have everything checked by an expert.
Some shops will not work on a bike more than 10 years old, parts get harder to find for old bikes, and it is a safety issue if some hidden wear suddenly causes a big failure while you are going 75 mph and surrounded by cars. I was reading about a guy with an old BMW that crashed while passing a truck from a tank slapper, and the mechanic inspection afterwards found that the steering head bearings were worn and probably caused the crash.
My favorite choices for a beginner are the 250cc and 500cc Kawasaki Ninjas. They have been big sellers for years, a lot of parts are available both new and used, motorcycle mechanics know a lot about them, and they are water cooled for longer engine life.
For a person always planning to ride solo, the 250 Ninja would cost less. For a passenger added (pillion rider), the 500 Ninja is better. Some race tracks have classes for both of these Ninjas, with the Suzuki SV650 or a modified Honda Hawk as the next step above them.