Most cysts, masses etc are benign. Also CA125s can be elevated for numerous reasons, including a tooth infection or swelling elsewhere in the body.
Your doctor is being proactive, and setting you up for the best possible chances, if by some chance is it cancer. GYN/Oncologists have 3 years additional education and training, they are the experts, and studies have shown, if, there is cancer, there is a better and longer survival rate if the surgery is done by a GYN/Oncologist.