“I used to be indecisive. Now, I’m not sure”

“I used to be indecisive, but now I’m not so sure” is a jocular saying that has been printed on many images. The saying has been cited in print since at least 1980.
       
   
25 October 1980, Pittsburgh (PA) Post-Gazette, “Book Choices” by James E. Alexander, Saturday Magazine, pg. 15, col. 1:
A British wit in the 1700s: I used to be indecisive, but now I’m not so sure.
(From Quote…Unquote by Nigel Rees.—ed.)
 
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October 1986, Boys’ Life, “Think & Grin,” pg. 66, col. 1:
Pedro says: “I used to be indecisive but now I’m not so sure.”— Alexander Kozak, Arlington, Va.
         
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The New Yorker
Volume 64, Issues 1-10
1988
Pg. 119:
A line assigned to his character in the show was “I used to be indecisive. Now I’m not so sure.”
 
Google Groups: alt.good.morning
I used to be indecisive, but now I’m not sure.
Roderick Parks
4/8/94
Good Afternoon!
 
Google Books
The Speaker’s Quote Book:
Over 4,500 Illustrations and Quotations for All Occasions
Edited by Roy B. Zuck
Grand Rapids, MI: Kregel Publications
1997
Pg. 210:
INDECISION
I used to be indecisive, but now I’m not so sure.
 
Google Groups: comp.sys.ibm.pc.soundcard.tech
I used to be indecisive…now I’m not sure…
.(JavaScript must be enabled to view this email address)
7/20/97
I have been thinking of upgrading my sound card.
 
20 November 1997, Vancouver (BC) Sun, “City limits,” pg. B5:
SIGNPOST
Robert in Port Moody says he followed a driver who couldn’t decide which way to turn at the four-way Stop sign, “and then I saw his bumper sticker and it explained everything”: I used to be indecisive—now I’m not sure.
 
10 July 1999, The Herald (Glasgow, Scotland), “Hill still in a spin over his future” by Hugh Hunston, pg. 14:
‘I used to be indecisive, now I’m not so sure,’ may have become Damon Hill’s anthem, but Coulthard has no plans to orchestrate his fans’ emotions.
 
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All Kinds of Humor:
Jokes, Quips, and Fun Stuff for Many Occasions, Book 1
By Frank Verano
Xlibris Corporation (Xlibris.com)
2012
Pg. 21:
I used to be indecisive. Now I’m not sure.
 
Google Books
Highly Tweetable:
5000+ Awesome Quotes to Use on Twitter and Social Media
By Devin Metzger
Pronoun
2016
Pg. ?:
I used to be indecisive, but now I’m not so sure.