I would advise against dividing this dendrobium orchid. It needs to grow and develop many more growths. The thing to remember about dendrobiums is that they like to be tightly potted in free draining mix. They grow best this way. Dividing when it is so small will only stunt the growth and possibly keep it from blooming anytime soon. Of course, someone else may have a different opinion, but from the photos you include, that is my best recommendation.