She was previously an assistant at Colgate University.

In 2019 Geremia-Mathers helped lead Colgate to a 5-4 record in the Patriot League and the Raiders advanced to the conference semifinals for the first time since 2015. She coached four all-league team honorees.

Geremia-Mathers was on the staff at Washington and Lee University in 2017 and 2018. During those two seasons the Generals went 35-7 including 16-0 in the Old Dominion Athletic Conference (ODAC), won two conference titles and made two NCAA Division III championship appearances. In 2017 she helped guide Washington and Lee to a team-record 19 wins as they advanced to the NCAA semifinals for the first time. The Generals collected the conference's coach of the year award in 2018. She coached four all-Americans, eight all-region and 19 all-conference selections, and a pair of conference players of the year.

Geremia-Mathers was one of the top offensive players in NCAA history during a four-year career that was split between SUNY Cortland and Le Moyne College. Her 490 career points are fifth-most all-time across all NCAA divisions and her 248 assists are good for third place. She was a four-time Intercollegiate Women's Lacrosse Coaches Association (IWLCA) first team all-American, the IWLCA Division III attacker of the year in 2014 and the Division II attacker of the year the following season. She was also a three-time Tewaaraton Award nominee.

At Le Moyne, Geremia-Mathers led the Dolphins to 36 wins and two trips to both the Northeast-10 Conference championship final and the NCAA Division II championship semifinals. She was voted the SUNYAC rookie of the year in 2013 after she racked up 62 goals and 74 assists for Cortland. She was selected the conference's player of the year in 2014 after a 124-point season. The Red Dragons went 43-3, won two conference titles and advanced to the NCAA semifinals twice with Geremia-Mathers.

Geremia-Mathers has served on the IWLCA Senior All-Star Game committee and attended the ODAC Women in Athletics Symposium and NCAA Women Coaches Academy. She holds a bachelor's degree in English language and literature from Le Moyne and has her master's degree in sport managament from Liberty University. She hails from Camillus, N.Y., and was a standout athlete at West Genesee High School. Geremia-Mathers and her husband Jeremy reside in Manlius.