"Age doesn’t matter unless you’re a cheese” is a jocular one-line saying that has appeared in many quotation collections, always credited to American actress Billie Burke (1884-1970). “Age, she (Burke—ed.) observes, is nothing at all, ‘unless you’re a cheese’” was cited in the Baltimore (MD) Sun in November 1959, when Burke was age 75.
Wikipedia: Billie Burke
Mary William Ethelbert Appleton “Billie” Burke (August 7, 1884 – May 14, 1970) was an American actress. She is primarily known to modern audiences as Glinda the Good Witch of the North in the musical film The Wizard of Oz. She was nominated for an Academy Award for her performance as Emily Kilbourne in Merrily We Live. Burke was also the wife of Florenz Ziegfeld, Jr., of Ziegfeld Follies fame, from 1914 until his death.
8 November 1959, The Sun (Baltimore, MD), “Billie Burke’s Advice To Women” by Helen Henry, pg. A4:
Age, she observes, is nothing at all, “unless you’re a cheese”; it is “not a matter of years but ... of spirit, good health, good fortune.
The Reader’s Digest
ACTRESS Billie Burke: “Age doesn’t matter unless you’re a cheese.”
—Jean Sharlcy in Detroit Free Press
23 February 1963, Boston (MA) Herald, “Marge” by Marjorie Mills, pg. 54, col. 1:
How about Billie Burke’s footnote to that in the January Reader’s Digest? “Age doesn’t matter unless you are a cheese.”
Google News Archive
12 January 1967, The Spokesman-Review (Spokane, WA), “Shop with Sue,” pg. 3, col. 7 ad:
Age doesn’t matter unless you’re a cheese.— Billie Burke
OCLC WorldCat record
Age doesn’t matter unless you’re a cheese : wisdom from our elders
Author: Kathryn Petras; Ross Petras
Publisher: New York : Workman, 2002.
Edition/Format: Book : English
The 2,548 Wittiest Things Anybody Ever Said
Edited by Robert Byrne
New York, NY: Touchstone (Simon & Schuster)
Age doesn’t matter, unless you’re a cheese.
—Billie Burke (1884–1970)