Except as otherwise provided by statute, on and after October 1, 1972, the terms “minor”, “infant” and “infancy” shall be deemed to refer to a person under the age of eighteen years and any person eighteen years of age or over shall be an adult for all purposes whatsoever and have the same legal capacity, rights, powers, privileges, duties, liabilities and responsibilities as persons heretofore had at twenty-one years of age, and “age of majority” shall be deemed to be eighteen years.