I first read through the guesses, so I wouldn't duplicate any. Then, with my brain functioning at 100% (that is 100% for my brain, which is about 3% for most folks) posted the 15th. Had to edit the post to the 17th after I rechecked and saw that Brenda had guessed the 15th. Then, I almost didn't check the thread, figuring there was no way.
I'm gonna have to start paying better attention. Or maybe not, it seems to work out okay when I'm clueless!