The provisions of this Act shall not affect the capacity of any person who, before the date of commencement of this Act, has attained majority under the law applicable to him.

Notwithstanding subsection (1) of this section, where by any instrument or by the order of any court a guardian has been appointed for any person until that person attains the age of twenty-one years, such appointment shall, unless otherwise ordered, continue until that person has attained the age of eighteen years or until the date of commencement of this Act, whichever is the later.

Where, under the provisions of any written law in force at the date of commencement of this Act, other than the Kenya Citizenship Act (Cap. 170), the expression "minor", "infant" or "full age" is used to refer to any different age, such expression shall be read and construed as a reference to the age of eighteen years.

For the purpose of this Act and any other written law, in computing the age of any person the day on which he was born shall be included as a whole day and he shall be deemed not to have attained such age as may be specified until the beginning of the relevant anniversary of the day of his birth.