YOU SAID:

Summer after high school, when we first met

INTO JAPANESE

高校卒業後の夏、初めて出会ったとき

BACK INTO ENGLISH

When I met for the first time in summer after my high school graduation

INTO JAPANESE

高校卒業後、初めて夏に会ったとき

BACK INTO ENGLISH

When I first met in the summer after I graduated from high school

INTO JAPANESE

高校卒業後の夏に初めて会ったとき

BACK INTO ENGLISH

When I first met in the summer after I graduated from high school