"It's one of the premier cross country courses," she said. "I like to watch the cross country runners here, it's natural."
Running came very naturally to Barrett as a girl.
"I just liked to run and do things like the boys did," she said.
But the idea of her running didn't come naturally to everyone else.
"In those days, they thought it was kind of strange to run," she said.
Running especially wasn't considered natural for girls in school, as Barrett found out when she sought to join the cross country team. There was no team for girls at her school: St. Rose Catholic School in central New Jersey.
"I actually ran with the boys team," she said, adding that the school coaches and teachers were very kind despite the shortage of opportunities for girl athletes at that time.
There was also a lack of opportunities for women in the Boston Marathon.
"The AAU wouldn't allow it at first," she said. "(They thought) it would hurt women, hurt the reproductive organs."
Barrett said one doctor at the time even asserted that a woman's uterus would "fall out" if she ran long distances.
In 1972, when Barrett was 17 years old, Title IX was just months from being signed. The new law would require that women and girls have equal access and funding for opportunities like sports.
As the historic legislation was about to be signed, Barrett just so happened to run the race of her life.
"I didn't expect to really run the marathon that fast at that point," she said.
To her surprise, it qualified her for the Boston Marathon, which had just decided to allow women to race.
After some convincing from her coach, Barrett decided to forgo her high school championship to become a part of history. She and eight other women became the first to ever officially run the Boston Marathon.
"It was exciting yet kind of nerve-wracking because we all have this unspoken agreement that we all have to finish this," she said.
This year's race, on Monday, will mark the 50th anniversary of women officially running in the Boston Marathon. However, unofficially, women have been running for longer.
"Roberta ("Bobbi") Gibb, she snuck in. Jumped out the bushes in 1966," Barrett said of the woman who attempted to force her way into the race. It led to the now-infamous picture of a male race organizer trying to forcibly remove her as she ran the race.
Women like Gibb, Barrett and others helped pave the way for people like Aimee Blanchette and Crystal Corley of the Wissahickon Wanderers trail running club. They now run alongside Barrett.
"I think now we know that was a huge glass ceiling she smashed," said Corley.
"And she's so humble about it," said Blanchette.
Fifty years after her historic run, Barret does more walking and stretching than running, but she's still headed to Boston for this year's marathon as five of the eight women will return to the race to be honored.
"They gave us a seat at the finish line. It's really cool," she said.
They're all being celebrated for a victory that went far beyond the finish line.
"It's nice to see other generations have that opportunity and enjoy it," Barrett said.