Teresa taught herself to swim in the local school pool when she was 10 years old. She began to play water polo for Swanson Primary School, playing for 3 years at intermediate level. She then moved on to Massey High School, where she played for both the school and the local club, Waitakere City Waterpolo. 

In 2005 she was selected for the Under 15 New Zealand team.

This began her successful representative career including Under 17, Under 18, Under 20, NZ School Girls and NZ Senior Women.

Towards the end of 2007 Teresa was encouraged by her swimming friend Sue to have a go at Stroke and Stride, a swim-run event held on the Auckland waterfront. She finished 15 ^th in her first race and was hooked. 

After talks with Triathlon NZ, she decided to take a break from waterpolo to pursue her new goals in triathlon.

Her first season was a huge learning curve, having never ridden a bike with gears before and with very limited running experience. Strong results allowed her to qualify for the Youth Olympic Festival in Australia in early 2009.