I majored in agriculture, and I want to go to Australia for graduate study and then immigrate.

You'd better study for two years as a graduate student. 1 year is of little basic use. Agriculture is, of course, an immigration major. Party member has nothing to do with immigration, as long as there are four sevens. After studying in Australia for two years, you can get a two-year visa, the approval time is 10 month, and you can stay in Australia unconditionally for about three years.