"Size Doesn't Matter"

[Joanne M. Despres]

Fred,

We don't have anything earlier than OED does for "shit or get off
the pot."  Here's what I could find for "size doesn't matter" -- though
I'm not sure it's the meaning you're after:

  Because of her|diminutiveness, Janet bore the|brunt of many
jokes.  At the U.S. Long Course Nationals in August 1985, Tiffany
Cohen, a double gold medalist at the 1984 Los Angeles Olympics
and the reigning U.S. dis-tance swimmer at the time,|snickered
when Janet hoisted herself out of a warmup pool. The 5'9", 139-
pound Cohen towered over the scrawny 5'1", 87-pound|upstart.
"That made me so mad," Evans says.  "I never saw myself as
being small.  Size doesn't matter as long as you can get to the end
of the pool faster than everybody else." "Meet a Small Wonder"

143 Jill Lieber SPORTS ILLUSTRATED  Vol. 69  No. 12
September 14, 1988

Joanne M. Despres, Senior Editor
Merriam-Webster, Inc.
jdespres at merriam-webster.com
http://www.merriam-webster.com