If you like sportbikes the conventional wisdom has been the Kawasaki Nijna 250. By far the best choice in a beginners ride is the Honda Rebel 250, or the Yamaha V-Star 250. The cruisers have a lower seat height, a lower center of gravity, are easier to ride and control and are generally less expensive. they are forgiving to inexperience and respond well to increases in skill and confidence.
If you don't have your motorcycle license, take the MSF cycle course. Its worth every penny, and you get your license at the end. Plus, they supply the bike.
Take the course. Listen to the instructors. Apply what they teach out here on the streets. Ride safe Stay alive. Don't give motorcycling a bad name.