What is Queens, and is it only one year?

Queens was a secondary school.... a teaching college. Anne spent one year in Queens.

Queens was a college where people could study to get their teaching certificate. Licenses for teaching varied and teachers were paid according to the level they achieved. Anne and Gilbert get their first class license in one year meaning that they took two years' of study load in one year. Josie, Moody and Charlie return to Queens for a second year to get their first class license. Jane and Ruby leave Queens after one year with a second class license.

Later, in Anne of the Island we read that Stella Maynard had done three years at Queens which qualified her to join the Sophomore year at Redmond College.