"I'm actually going in high hopes," said Sean. "It's because of things like this that my mom was a survivor."
We first met Sean's mother, Lori, in 2006, a year after she was diagnosed with breast cancer. She was taking part in the three-day walk with her friends to raise money and awareness to fight the disease.
"She just said, 'Sean, I have breast cancer,'" said Sean back in 2006. "We're all like, 'No way,' and we were all sad."
Back then, Sean, not old enough to take part in the walk, could only cheer his mom on. Until now.
"This is actually kind of come full circle now," said Lori Feeney. "I'm healthy, thank god, and everything is good and now my son, who is 16 and is just now old enough to walk in the three-day walk, has kind of taken up the reins. I'm very, very proud. It's a really proud moment."
Sean turned to his best friends to form "Team Impact."
"Because of Sean's mom, she went through breast cancer, so she's like the living testament to all this and so that inspired us to do it," said student Trevor Brown.
"It's really emotional, believe me," said Lori. "These are 16- and 17-year-old boys. Breast cancer, this is so far out of their radar. And here they are now taking time out of their lives to train, to fundraise."
Team Impact's goal is to raise nearly $30,000. They're almost at $28,000 as they set out on their journey."
The walk begins at the Del Mar Fairgrounds. They'll be walking through various communities in San Diego County, averaging about 20 miles a day.
"Twenty miles a day -- it might get long on that last day," said Trevor.
"We're ready," said Sean. "We're ready for it."