For purposes of this chapter, the age of entry into this system as a member in any membership category for a person who enters on or after October 1, 1957, and within 90 days after last rendering service as a member of a county retirement system and who retains his or her membership in that system shall be his or her age at entry into the county retirement system.

(Amended by Stats. 1996, Ch. 906, Sec. 76. Effective January 1, 1997.)