Tinka Mathews and her family wore pink shirts with the words "Team Marisa" on the front at Crescenta Valley High School's commencement ceremony on Thursday at Stengel Field.
Mathews' younger sister, Marisa Szeps, 18, was one of 640 graduates earning their high school diplomas.
"It's exciting and heart breaking," Mathews said. "We are all very proud of her."
That included Szeps' grandmother, who came from Argentina for the graduation.
Pride in their education was not in short supply Thursday, as students spoke of life after high school.
"It's a huge accomplishment," Rachel Whitaker, 18, said of graduation. "It's the end of one of the chapters of our life."