Legal analysis: you will not quit the league automatically after graduating from college. According to the articles of association, when you are 28 years old, you can't keep your league membership.

Legal basis: Articles of Association of the Youth League of China * * * Article 1 Young people in China who have reached the age of 14 but under the age of 28, recognize the articles of association of the Youth League, are willing to join an organization of the Youth League and work actively in it, implement the resolutions of the Youth League and pay the tour fee on time, may apply to join the Youth League of China * * *. Members who have reached the age of 28 and have not held positions in the group should go through the formalities of withdrawing from the group. After joining the * * * production party, members still retain their membership. Those who have reached the age of 28 and have not held positions in the group will no longer retain their membership.