Sara is a minor character of the popular animated TV series, Phineas and Ferb. She is the cousin of Jenny who comes to Candace's party (or as Candace calls it, her "intimate get-together"). She meets Candace for the first time, but she knows or has heard of her brothers. Sara probably lives in Danville or comes to visit her cousin on vacation. Jenny said that she came to pass the weekend at Jenny's house ("Candace Gets Busted").
Sara tends to get overexcited. At Candace's "intimate get together", she wouldn't stop turning up the music and dancing. Also when she found out it was Phineas and Ferb's house, she recognized Candace as Phineas and Ferb's sister.