A 2026 graduate of Savanna High School, the Anaheim, California native earned four letters in soccer and two in flag football for the Rebels. She competed at the Division 6 level under head coaches Jose Gonzales and Nicole Valdez, helping Savanna win the Orange League as a sophomore in 2023-24 and the Grove League as a senior in 2025-26. Alvarado made Second Team All-Orange League as a sophomore. By her junior season she had progressed to First Team All-Coast League honors and the team's Most Valuable Player award, adding three-time California Interscholastic Federation recognition.

Outside of the high school ranks, Alvarado played club soccer for West Coast FC in the Girls Academy League. The team reached the playoffs three consecutive seasons, from 2022-25, and qualified for the National Finals in back-to-back years, finishing sixth nationally in 2024-25 and 15th the following season. West Coast FC also placed third in the Southwest Conference in 2023-24, won the league outright the next year, and finished as runner-up in 2025-26.

Sophia is the daughter of Sophia Alvarado and plans to study accounting.