Tiareti fought alongside the Commonwealth forces in Gallipoli and Italy during World War I.
Trinity, who lives in Bowentown, said she felt privileged to stand in front of the crowd wearing the traditional cloak to the gold and green of her college. The cloak was made as part of the school's kapa haka group.
Trinity's grandmother, Tiareti's daughter, Sue Gardiner attended the service and said she hoped more students would join in the future.