Read more in the Dragon Journal of Taijiquan where you can find many posts on the what, why and how of tai chi and qigong.
You can discover a wide variety of results by doing tai chi. This I can say with confidence because it's been proven over and over again in research and in anecdotal stories from people, such as myself, who have practiced tai chi. Not just people who have practiced for a long time, but people just beginning. Many feel it in their first class.
Bring some effort into learning it in the initial stages in order can bring positive, healthy results into life: mental, physical, psychological, emotional, and even spiritual health. How all that applies can differ from person-to-person, so ask yourself what it may mean to you. It takes time and the results are directly related to the effort you make.
Zhong ding (area-spinal column) translates as "central equilibrium" and dantian (area-abdomen) is "field of elixir." Zhong ding and dantian can be applied in any type of movement, not only tai chi. Combined in practice, they form a powerful method for what we call "whole body moves as a single unit" that delivers many benefits: better balance, posture, coordination, endurance, circulation, even memory, and often a deep sense of well-being, to name a few. Together these tools form a basis for movement in general as well as martial arts movement.