Don't rush! If you are confident, and your position is good, and you can ride bareback at at least the trot and ride with no stirrups at the canter without getting off ballance, by all means you should definitely start jumping! Of course, I couldn't be one to say much because my past instructors didn't pay much attention to my position and just let me jump at only 4 months of riding. Now that I have a better instructor, I'm learning to get better position, and it's challenging. So make sure your position is perfect before you jump.
Start with a little cavaletti and see how you do. If your comfaterable enough, keep jumping, and if your not, stick to flatwork and groundpoles until your position is better.