When a carillonneur-in-training makes a mistake on the Peace Tower bells during her final exam, it's hard to miss, especially if it's a note in O Canada.

But 72-year-old Wendy Stokes-Earl isn't deterred.

She's been a pipe organist for 40 years, but after hearing carillon bells on vacation in Florida in 2003, she decided to learn those, too.

"We sat under the trees, watching the squirrels in the sunshine, listening to jazz, blues, gospel on bells. It was magical," Stokes-Earl recently told CBC Radio's Ottawa Morning.

'Seemed a natural progression'

Then, in 2015, Rick Mercer did a piece on the Dominion Carillonneur, Andrea McCrady, and Stokes-Earl was inspired to reach out.

"I knew that this lady was approachable, so I just sent her an email and asked, 'Have you ever thought of having a rather senior student?' And she answered almost immediately and said, 'Sure, come on up and we'll talk about it.' And we did," she recalled.

"It seemed a natural progression, from the pipe organ to the carillon. I thought it would be an easy progression because I was used to moving my feet around independently from my hands and so on. That was not the case. It's a completely different pedal technique, and I have yet to master it."

Andrea McCrady has been the Dominion Carillonneur of Canada since 2008. (Robyn Bresnahan/CBC)

Carillons are hard to come by, but there's a practice keyboard at Carleton University, another in McCrady's office on Parliament Hill, and of course there's the real thing in the Peace Tower.

It's been a sometimes frustrating journey to learn the carillon bells, but Stokes-Earl said it's been worth it.

"I was having my final exam, and I did muff up O Canada. One note missed. And of course, everybody knows that one," she said.

"One should keep learning, all the time. Lifelong learning is, I think, the secret to lifelong youth."