Determining an average age is really impossible, joriebelle. Some retire in their late twenties after only a few years of performing, many go well into or through their thirties, and some well beyond that. Companies that perform large classical works keep some of their dancers for character roles, such as Kings and Queens and other roles which require more acting than dancing, such as Giselle's mother, Lady Capulet, Don Quixote, etc. etc. Many teach, coach, become ballet masters/mistresses, directors of companies, directors of schools, or choreographers. Some do all those things! Many travel around the world staging works they danced. There are many who remain in dance for the rest of their lives, and many who go back to school and work in totally different fields.