Section 13-164. Retirement; selection of age fifty-five

Notwithstanding the
  provisions of section 13-151 of this  chapter,  any  person  becoming  a
  member  who  was not previously a member or who during his last previous
  membership in the retirement  system  contributed  on  the  basis  of  a
  minimum   retirement   age  of  fifty-five,  may  elect,  prior  to  the
  certification of his or her rate of contribution;  and  any  member  may
  elect,  prior  to the first day of October, nineteen hundred forty-nine,
  to contribute on the basis of a minimum retirement age of fifty-five  by
  a  written  election  duly  executed and acknowledged and filed with the
  board. The minimum age of retirement for such member so  electing  shall
  be fifty-five years, and all contributions and benefits payable by or on
  account  of  such  member shall be computed on the basis of such minimum
  retirement age. The method of computation and deductions  prescribed  by
  this section shall be appropriately modified in the case of a member for
  whom  a  rate  is  otherwise  fixed  pursuant  to section 13-152 of this
  chapter.