Pinder played field hockey for St. Andrew's College in a team that also included her sister, Laura and Chloe Watkins. She played in three Leinster Schoolgirls' Senior Cup finals, regularly playing against teams that included future Ireland teammates. In the 2007 final, Pinder and Watkins lost 5–0 to an Alexandra College team that featured Nicola Evans. In the 2009 final St. Andrew's faced Loreto, Beaufort and Hannah Matthews. This time St. Andrew's won 2–0 after extra time. In the 2010 final Pinder scored the opening goal in a 2–0 win. Watkins captained St. Andrew's as they defeated an Alexandra College team that featured Deirdre Duke and Emily Beatty. In 2010 Pinder and Watkins were also members of the St. Andrew's College team that won the Kate Russell All-Ireland Schoolgirls Championship, defeating Coláiste Iognáid, Galway 3–1 in the final. On 10 September 2018, after their success at the Women's Hockey World Cup, Watkins and Pinder returned to St. Andrew's to share their experience with the current students at St. Andrew's. Pinder also began managing the hockey programme at St. Andrew's.