ST PETER — Last February, Leah Matz turned an anti-lesbian slur on her locker into an opportunity for learning, mobilizing St. Peter High School with a rally that drew hundreds of people.

Since then, she’s become a student organizer for a national organization that’s calling attention to the abuse faced by gays and lesbians in schools.

She also left the high school shortly after the demonstration, which she called “sort of my swan song.”

Matz, who is a lesbian, said her decision to switch to New Country School in Henderson was based on both the continuing harassment she received and academic listlessness.

“I was bored,” the 15-year-old said simply.

As a part of the Gay, Lesbian and Straight Education Network, or GLSEN, Matz has spoken to high schools, colleges and media outlets. That included an appearance on a morning show on the Fox network.

With GLSEN, she’s turned her attention to a phrase on the lips of teenagers — “that’s so gay” — to refer to something distasteful or unpleasant.

While many teenagers use it without thinking, Matz says it’s a slur that insults gays and lesbians by referring to their sexuality as a negative.

This use of “gay” is one of a line of defamatory uses of words that has seeped into the language. Other examples include “dumb,” a word for people who can’t speak, and “lame,” which refers to a physical disability, she said.

“I’m very afraid that it’s going to become so casual and so second nature to say it, that it’ll fall right along with ‘that’s lame’ or ‘that’s dumb’ and we’ll say it all the time,” she said.

Given her public activism, Matz can’t help but be out of the closet as a lesbian at her new school. She tends not to get harassed at school, and while she does hear things, she does not tolerate them.

“If I’m around and somebody says, ‘That’s so gay,’ I will look at them and they say, ‘I’m sorry,’” she said.

Her next project: Persuade the Minnesota School Boards Association to widen its bullying policy to specifically mention harassment based on sexual orientation and gender identity and expression.

Matz was one of hundreds who applied to be a GLSEN student organizer, and only about 40 made it.

“Leah really stood out as someone who had not only the organizing skills but also the motivating skills to help make schools safer in her community,” said GLSEN spokesman Daryl Presgraves.

Communication about the issues is important for GLSEN’s organizers, he said.

“If you talk to Leah, you get a sense for how inspirational she is and how she connects with people,” Presgraves said.

Matz said the lessons she learned at her St. Peter High School rally have changed her.

“Before, I guess I felt that any work that I did was helpful in a small regard,” she said.

But now, after seeing strangers wearing the “Stop hate. Just love” T-shirts she helped make for the rally, Matz believes “with the help of other people, we can really do amazing things for the world.”