Distribution of GPA

Hi! So I am currently a junior. I am going to have to take an extra semester to complete my bachelors degree because I switched my major pretty late and I had a minor too. I was just wondering what the distribution of my GPA would look like since I am going to have an extra semester. Would everything from my senior year and the extra semester come up as my senior year GPA or would classes that I take in the first semester of Senior year go into my junior GPA and the rest would stay for senior GPA?