For most high schoolers, the big concerns are getting into college or fitting in with their peers.
For Courtney Simmons, there was also cancer.
She was diagnosed in her junior year, one week after she lost her mother to different cancer.
"It was right under my knee cap - this is technically my proximal tibia," said Courtney.
Courtney had osteosarcoma - a bone cancer.
It is among the most common cancers in adolescents. Others include:
* Lymphomas - centered in the immune system
* Testicular cancer in boys
* Cervical or ovarian cancer in girls
In the past 40 years, rates of skin cancer have skyrocketed in both boys and girls, possibly due to the popularity of indoor tanning.
Dr. Frank Balis, of Children's Hospital of Philadelphia, says treatments are the same as for other age groups, but different for older children.
"Older children, adolescents, and young adults may not tolerate the treatments as well as young children," said Dr. Balis.
Courtney had 10 months of chemotherapy, and in the middle, surgery to remove the tumor.
"They replaced here to here with titanium, and a full knee replacement," said Courtney.
Like many teens, Courtney struggled with the emotional side of losing her hair.
"I couldn't change it, so I had to accept it, and I began to embrace it," she said.
80-percent of adolescents with cancer will survive, but two-thirds develop complications such as a secondary cancer, heart or lung damage, or infertility.
"Many of the drugs we use can have an effect on a person's ability to have children later in life," explained Dr. Balis.
At Children's Hospital of Philadelphia, a fertility preservation program starts as soon as the cancer is diagnosed.
Survivors will need to be monitored throughout their lives.
Courtney is now cancer-free, and she is focused on one goal - to become a pediatric cancer nurse. She is hoping to help others through their battles.