The ca-125 test is not accurate at diagnosing ovarian cancer. Benign conditions including benign ovarian cysts can cause an elevated result / false positive. Ovarian cancer is rare especially if you do not have a family history. Is there anyone in your family who has had ovarian cancer?
Most ovarian cysts are benign / non-cancerous and resolve on their own, no intervention needed. However since yours is on the large side it may need to be surgically removed.
If you do need surgery it is very much to your benefit to keep the ovary and just have the cyst removed which is called a cystectomy. Removal of one ovary can cause permanent problems. It can cause infertility but also permanent health problems. One study showed an increased risk of cognitive impairment dementia and parkinsonism and women who had one ovary removed.
If the frozen section done while you are in the operating room shows that the cyst is benign then you should not need to lose any organs you have a surgeon with good cystectomy skills. Unfortunately far too many women lose an ovary / ovaries for benign ovarian cysts.
If they were concerned about cancer, they'd be doing surgery. So cancer must not be a concern.