17-year-old Helena Muffly wrote exactly 100 years ago today:
Wednesday 9, 1912:My head is all in a muddle, and I hardly know how to think.
Her middle-aged granddaughter’s comments 100 years later:
I’m going to remember the word “muddle.” No more senior moments for me—from now on my head is going to just be in a muddle whenever I make a silly mistake.
Why was Grandma’s head in a muddle? Was something wrong? Was she worried about something?
Whatever was bothering her has been lost over time. Too bad she didn’t record it in the diary.
A Hundred Years Ago 
Makes me think of the expression, muddling through…
I sympathize with her. My head has been in a muddle lately too.
Sounds like she’s been overloaded with school issues lately.