(KERO) — Pfizer-BioNtech announced Wednesday that its COVID vaccine is 100 percent protective in kids as young as 12. And now one teen is talking about her experience in the vaccine trial.

Since January 13-year-old Emma Kate Stibler has been participating in Pfizer's vaccine trial for pediatric patients, which includes kids from ages 12 to 15. The preliminary data from the study showed that of over 2,200 participants there were no COVID cases among teenagers who were fully vaccinated.

Researchers also reported finding high levels of the virus-fighting antibodies.

Stibler doesn't know if she got a dummy shot or the real vaccine but she has a guess.

"I think I probably did get the real one because I had a sore arm and a slight fever, and I was tired," she said.

Stibler says she still gets tested for COVID regularly and gives blood.

The study will continue to track participants for two years. Pfizer has already started testing the next age group, six months to 11 years of age.