She got involved in SADD because "our school has lost a few students to drunk driving". "I thought that if I joined up I would be able to make a difference".
The difference, says Erin, is in educating her peers how to be responsible.
"We're not there to ruin fun, it's not that we are anti-drinking, but once the first drink has been opened, then the car keys need to be put in a safe place."
The year-long position with SADD will, says Erin, give her opportunities to reach far more teenagers than just those who attend Inglewood High School.
"As well as travelling around New Zealand to talk to other teens, we will get input into the way the programmes are delivered in schools and can make it relevant to them."
The key messages are simple, she adds: "Think before you drink and watch out for your mates."