I'm the exact same size as you, but I've been able to grab rim since high school. I've never been able to dunk though. Its a plus that you can palm the ball, which I have a little trouble doing. However, you need to have your dunking hand several inches above the rim in order to dunk. Depending on what part of the net you are touching that could be anywhere from 6 inches to a foot that you need to improve your vertical. That is quite an obstacle. Jumping is kind of a natural talent like a pure sprint is. But best of luck anyway.