As with almost any learning, the earlier you start the better.
From a teacher
depends on the person not the art. Personally i feel tai chi is a more complete fighting style. It takes much longer to learn tho. Tai Chi is more a grappling art.
There is a DVD that shows 20 of America's best known Tai-chi teachers performing forms, push hands, weapons forms and sparring and the lion dance. It is called "The Best of American Tai-chi".
The most popular Tai Chi DVD series are The Tai Chi - 24 Hours, Sunrise Tai Chi, Totaly Nude Yoga and Tai chi, Tai Chi for Health - Yang Short Form with Terrence Dunn etc.
Tai Chi comes from China.
Ku style Tai Chi does exist, as well as Wu style; and many other styles of Tai Chi. Katara studies Ku style/Yang form Tai Chi, Sun style Tai Chi, and Bikram Yoga.
tai gik is the cantonese pronunciation. tai chi is mandarin.
in what ways is tai chi powerful
Quo Tai-chi was born in 1889.
Quo Tai-chi died in 1952.
Yes, weapons are used in tai chi.
Tai Chi-tao was born in 1890.