No. Eligibility for the earned income tax credit is based on income, not age. The amount of the credit varies with the number of qualifying children you have. A modest credit applies even if you have no such child; the credit amount (and the income limits for eligibility) scales up for one child, two, children, or three or more children.
An individual who operates a business or profession as a proprietor or independent contractor and reports self-employment income on Schedule C.