"If you write with a white pen you will speak the truth"
Within the first few minutes of meeting someone in a golf lesson capacity, I will have made a decision about how good that person can possibly become at golf. This isn't a conscious decision, it just happens, and it helps me to focus my mind on the task at hand, which is to help that person achieve their potential.
I think that very few people would agree with me regarding my estimation of their ability, the majority would think I am slightly crazy.
You can be as good as I think you can be, but I'm not going to tell you how good you can be. If you would like to know how good I think you can be, allow yourself to imagine a standard of golfing prowess that you would have to achieve in order to be capable of playing slightly beyond your wildest dreams. This is how good I think you can be. Now it may be that I am crazy, or I could possibly be right, it doesn't really matter. Either way, it is no harm for you to have a dream.