Gentlemen, if my sources are correct, a kimono for a man or woman may be formal or informal.
Women's kimono formality is generally recognized by material (polyester less formal than silk), color and amount of decoration, the obi material and style of tying, and sleeve length (not just determined by marital status).
The formal kimono for a wedding includes a furisode .... most often recognized by westerners by the extremely long sleeves. One version of the undergarment is a juban.
A woman does not require assistance to dress in a kimono, but she would be crazy to decline it.
If anyone wants extensive detail on this, check out the web site for Immortal Geisha and the numerous topics regarding kimono.