Burn out? It’s not in Gloria Sfiroudis’ vocabulary.

The 50-year veteran teacher headed back to PS 229 in Woodside in September with as much bounce in her step as she had in 1953 when, right out of Hunter College, she first set foot in a classroom.

That was 60 years ago. Subtract 10 years for maternity leave and this marks Sfiroudis’ 51st school year.

With an eye on the future more than the past, Sfiroudis acknowledges that in some ways the more things change, the more they stay the same. “We still have kids in need today, and we still have budgets,” she observed.

But she also remembers having to write “lesson plans like they were written for publication” and earning $3,200 a year.

From the vantage point of all her years of teaching, from “opportunity classes” — the name for classes for students with disabilities before special education — to gifted and talented classes, from reading specialist to the library teacher she is today, Sfiroudis thinks schools have changed for the better. Schools, she says, now do a much better job of supporting special-needs children and listening to parents.

PS 229 Chapter Leader Loretta Tumbarello marvels at Sfiroudis’ ability to deal with change.

“She goes with the flow,” she said. Between sessions staffing the phone banks this summer at the UFT’s Queens borough office, Sfiroudis recalled her indignation when she was asked to join the union in its early struggle to organize teachers.

“What do you think I am, a coal miner?” she snapped at the union organizer. But when she got to thinking about her coal miner grandfather, she realized she needed union protection as much as he had. And so began her enduring role as an activist that stretches from the picket lines of 1954 to today.

She remembers taking her children to school while she was on maternity leave only to find a picket line. She didn’t cross the 1968 strike line and was remembered for that support by PS 229 staff when she was hired at the school two years later. That came about after she was plucked from the audience and stepped into the breach, unrehearsed, to play the piano in her child’s school Christmas show.

The auditorium was packed and the curtain was about to go up, but the teacher scheduled to play was caught in traffic and never made it. An appreciative principal, when he discovered Sfiroudis was an experienced teacher, offered her a job.

As guardian of the PS 229 library, Sfiroudis won a $75,000 grant that she used to build a strong nonfiction section and oversaw the modernization of the library six years ago. Last year, the students checked out 16,000 books, a record that she hopes to beat this year.

When Sfiroudis was honored for her “dedication and service” in April at the District 24 Scholarship Dinner Dance, District Representative Rosemary Parker said young teachers, including some who were her former students, crowded around to congratulate her and express their appreciation. “You can always count on her to counsel the younger members on the importance of the union,” Parker added.

To ensure she’s in shape for her busy agenda, Sfiroudis heads for the pool to do 30 laps several times a week.

Retirement? She hasn’t given it a thought.

“My philosophy is that age is just a number,” she said, “as long as you remain young at heart, young in spirit and adventurous.”