THIRTY YEARS ago, on one of her first days at St. Anthony High School, Sister Alan Barszczewski confronted some menacing teenagers in the hallway.

Anyone would've felt cowed by the boys. They towered over Sister Alan, who stands a shrimpy 5 feet 3. And they were rough in a way she'd never experienced during the years she headed a serene Delaware academy for girls, where the bathrooms' adorable soap dishes were shaped like frogs.

St. Anthony - a hard-scrabble, co-ed school in a poor neighborhood of Jersey City - was a world away from Delaware.

But not from make-you-or-break-you Fishtown, where Sister grew up.

She glared up at those hallway toughs and hissed, "You don't scare me. I'm from Philly."

"They were shocked that this short nun would get in their face, but I had to prove myself at the very start or it would've been all over," said Sister, laughing at the memory.

That the boys came to respect her, and the many who have stayed in touch with her and the school staff are a testament to the everyday miracles that occur at St. Anthony - a small school with a big claim to fame. Its boys basketball team, the Friars, has won more championships than any other high school in the country.

In 2005, sportswriter Adrian Wojnarowski published a wonderful book about the place, The Miracle of St. Anthony: A Season with Coach Bob Hurley and Basketball's Most Improbable Dynasty.

It's now being made into a movie - actress Kathy Bates will play Sister Alan - and film crews bringing Tinseltown excitement to a neighborhood no one would confuse with Hollywood.

"This is a special place," said Sister, 62, as we toured the school, where she now oversees development.

"It has heart. The students come from a lot of poverty and challenges. They're nurtured here. We're hard on them, but it's tough love."

Just then, a tall, lanky student flung an arm around her, before ducking into his next class.

Smiling, she said, "There's nothing like a hug from a St. Anthony student."

The thing is, she shouldn't even be here to enjoy it.

In 2001, Sister Alan was diagnosed with liver cancer and given six months to live. Aggressive treatment at Memorial Sloan-Kettering Cancer Center has extended her life longer than anyone dared hope.

"I get tired from the chemo," she said as she sat in her skinny office, a converted coat room. "But once I get here, I catch the energy of the students."

Born in Fishtown, she went to Immaculate Conception High School in Lodi, N.J., after eighth grade to become a Felician nun. She's been moving at warp speed ever since, going on to teach, to work in a hospital and a nursing home and then to head that sweet girls' academy, where she thought she'd stay forever.

"God had other plans," she said of the day she was transferred to St. Anthony, a school in such bad financial shape, the archdiocese planned to close it.

Instead, she and a colleague, Sister Felicia, conspired with Coach Bob Hurley to keep the doors open.

It's now an independent school that attracts high-profile donors who believe in its mission, but fundraising remains a struggle.

"Each year, we wonder, 'How tight will it be this time?' " she said. "It's always a squeeze."

Some days, her devotion to the school gets the better of her, as I learned in a phone call just yesterday from her brother-in-law, Gene Lynam.

He told me that Sister Alan (her family calls her Rosemary, her birth name), had just been hospitalized for medical complications probably brought on by trying to do too much for others, not enough for herself.

"It's a Catch-22 with Rosemary," he said. "Her drive is what's helped her to survive so long. But it can also wear her out. She doesn't know how to slow down."

Nor does she want to, really.

As she explained, after 30 years of "St. Anthony hugs" from students now old enough to enroll their own kids in the school, it's hard to find a reason to back away from what the students call their "Friar Family."

Across the school's lobby stretches a welcoming banner. It reads: "You Are Entering a Special and Safe Place. The Streets Stop Here."

And the miracles begin.

As Sister Alan, forever a Philly girl, recovers at home, let's pray for another.

No one deserves it more. *

E-mail or call 215-854-2217. For recent columns: Read Ronnie's blog at ronnieblog.