Grossman attended Harvard-Westlake High School (Class of 2011), earning four letters in water polo and captain of the water polo team her final two years.[1][2][3] Her senior year she was named All-American, CIF Southern Section Division I Player of the Year, and Mission League MVP.[2] She competed in the 2009 and 2011 Junior World Water Polo Championships, and was named MVP of the 2010 Junior Olympics.[2][4] In 2011, she and high school baseball player Max Fried won the Southern California Jewish Sports Hall of Fame High School Award.[5][6][4]
She then attended Stanford University (Class of 2014, majoring in Science, Technology and Society), and with the water polo team winning three NCAA championships.[1][7] As a freshman in 2012, playing for the Stanford Cardinal water polo team at the 2-meter position, Grossman was Association of College Water Polo Coaches (ACWPC) All-America Honorable Mention, ACWPC All-Academic - Excellent, All-Mountain Pacific Sports Federation (MPSF) Honorable Mention, and named to the MPSF All-Newcomer Team.[2][8] As a sophomore in 2013, she was ACWPC All-Academic - Superior, and MPSF All-Academic.[2] As a junior in 2014, she was ACWPC All-America Honorable Mention, ACWPC All-Academic - Superior, All-MPSF Honorable Mention, and MPSF All-Academic.[2] As a senior in 2015, she was ACWPC First Team All-American, ACWPC All-Academic - Superior, All-NCAA Tournament First Team, All-MPSF Second Team, and MPSF All-Academic.[2] She finished her college career 10th in Stanford history, with 169 goals.[2][8] She was the co-recipient of the Pam Strathairn Award at the Stanford Athletic Board Awards, for her competitive attitude.[7] In 2016, she was awarded an NCAA postgraduate scholarship for her academic and athletic achievements.[7]