Anne with an E' s Miranda McKeon, 19, Plans to Attend USC While Continuing Breast Cancer Treatments

Anne with an E' s Miranda McKeon, 19, Plans to Attend USC While Continuing Breast Cancer Treatments

Like many college students, Miranda McKeon is eager to start her fall semester — as a sophomore at the University of Southern California. "I'm looking forward to the little moments, laughing with my friends about nothing," McKeon, 19, tells PEOPLE in this week's issue. "Little things that people don't think about but that make up all the joy you feel."

Focusing on life's joys is a priority these days. McKeon, of Ridgewood, NJ — who started her showbiz career in the sixth grade in off-Broadway's Little Miss Sunshine and plays Josie Pye in the Netflix series Anne with an 'E' — received the shocking diagnosis of stage 3 breast cancer in June.

"Although I don't have the best-case scenario," says McKeon, "I've never had a moment where I thought, 'Am I going to die from this?' "

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Hoping to spread awareness, she's candidly shared the ups and downs of her journey on her Instagram @Miranda.McKeon, where she has 1 million followers, as well as on her blog, MirandaMcKeon.com.

miranda mckeon
miranda mckeon

Patty Connelly Photography

"As statistics go, I am one in a million," she wrote on June 18, "... literally-look it up on Google." (Breast cancer is extremely rare in women 15 to 19. The National Cancer Institute reports 2 cases per million women annually.)

A June 21 PET scan revealed the cancer had not spread beyond her right breast and right lymph nodes — hopeful results celebrated with a pink party thrown by her high school pals. "Pink hair, all these crazy decorations," McKeon says. "When my whole world is crashing, my friends do the most awesome job of picking up the pieces."

miranda mckeon
miranda mckeon

Cout4esy Miranda Mckeon

For more of Miranda McKeon's breast cancer story, pick up a copy of PEOPLE on newsstands Friday

In fact, it was with friends at the Jersey Shore on May 30 when McKeon felt a lump in her breast while adjusting her shirt. "I was pretty freaked out," she tells PEOPLE. "After I went down a little Google rabbit hole, I assumed nothing was wrong because of my age and no family history of cancer."

Yet she immediately scheduled a doctor's appointment, which led to an ultrasound and a biopsy of the lump. In the the weeks since her diagnosis, McKeon's life has been filled with a whirlwind of tests, scans, fertility treatments (she had her eggs extracted and frozen as a precaution) and, now, chemotherapy at New York City's Memorial Sloan-Kettering Cancer Center. (On July 20 she wrote in her blog: "I recently discovered I have a Check 2 gene mutation, probably the cause of my cancer.")

After four months of chemo, she'll have surgery and then radiation.

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"It hits hard that my baby girl has breast cancer, but I could not be more proud of how she's handling things," Miranda's mom, Jill, a yoga instructor, tells PEOPLE. "From the time she was little, she's been a positive person. If she didn't make the tennis team, the next day she was figuring out how to join track."

While the chemo has made her feel "overall crummy" at times — her second treatment was last Monday — Miranda continues to work out, surf, take walks and hang out with friends on Monday nights to watch The Bachelorette.

As long as she keeps tolerating her treatments well, Miranda will be returning to USC in late August, where she'll continue chemo (Jill is moving nearby to help), write — which she calls her "therapy" — and explore new passions of earth science and oceanography. She also hopes to join the school hiking club and possibly an improv club, and to get involved in school shows. "There's more to come," says Miranda. "I won't let this stop me from living."