Marina Mason graduated from Brentwood High School in 2025 with 979 career strikeouts. A year later, the former Bruins ace was a first-team All-Big Ten pitcher and a consensus Freshman All-American at Northwestern.

Mason pitched four varsity seasons at Brentwood for Jessie Brown and her father, David Mason. She threw at least 125 innings each year and struck out more than 200 batters in three straight seasons, finishing with a 2.49 ERA over 584 innings. She earned District 11 Rookie of the Year honors as a freshman, twice won District 11 Pitcher of the Year, and twice made the Tennessee Sports Writers Association All-State team. Her best season came as a senior, when she struck out 339 batters and walked just 38. Northwestern lists that strikeout total as first in Tennessee and 12th nationally. She was also named the 2025 Williamson County MVP.

Wearing No. 24 for Northwestern in spring 2026, Mason went 18–9 with a 2.31 ERA and 182 strikeouts in 157⅓ innings. Opponents hit just .182 against her, and she threw eight shutouts. She was even better in Big Ten play, going 13–3 with a 2.00 ERA and 101 strikeouts. She won all 10 of her final regular-season appearances, capping that run with a one-hit shutout of Minnesota. Mason struck out a season-high 12 in the 6–0 win and earned both Big Ten Pitcher and Freshman of the Week honors. Her freshman season also earned her a spot among the 10 finalists for NFCA National Freshman of the Year and a first-team Freshman All-American selection from D1Softball. In her first spring of college softball, the pitcher who led Tennessee in strikeouts as a senior became a first-team all-conference selection in the Big Ten.