You have a good memory. Holden Caulfield did live in New York and was particularly fond of Greenwich Village. Holden met Jane Gallagher when their families were on summer vacation in Maine. The first meeting between the friends took place in 1948. Salinger used memories from his own childhood when he spent summer vacations in Maine with his family.
Later Holden went to Pencey and Jane went to Shipley. Note that Salinger originally stated that Jane went to B.M. but then changed it except for one place in the text.
Even though Jane and Holden go their separate ways, Jane continues to have a profound and lasting effect on Holden which often causes him to alter his behavior.