Ashley Park was diagnosed with cancer at 15. What she's learned.

Ashley Park discussed her childhood cancer journey at SXSW in Austin March 14.

AUSTIN — Ashley Park didn't want to go to the emergency room. She just wanted to rehearse for her "American Idol"-inspired show at school.

The "Emily in Paris" star was 15 years old when she started getting ill all the time. Huge bruises scattered her body. Park passed out during a dance class, showed up late to all her classes because she couldn't walk fast enough. She finally visited her doctor for a check-up, and was later diagnosed with acute myeloid leukemia.

"They're like, 'you have to go to the emergency room right away.' And I was like, 'I need to go to rehearsal first,'" Park, 34, told USA TODAY at SXSW on March 14. She was there to speak about the Time Back campaign, which recognizes oncologists and what they do for those living with cancer.

"We need a lot of positive things right now in the world, and I think that I haven't gotten to speak about regaining the moments that are positive and good when it has to do with my cancer experience," she says.

Acute myeloid leukemia begins in the bone marrow and typically invades the bloodstream thereafter, according to the American Cancer Society. It's rare and symptoms may appear innocent, like what you'd have with a cold or the flu. Treatment options often include chemotherapy and a bone marrow transplant.