Could The Tumor In Ovary Be Malignant?

Hi, Im a lady 31 years old diagnosed with an 8 cm tumor on the left ovary. I had all the blod test done and the results were normal, im wating to have the MRI scan so after that my date of operation can be decided. I am a mother of 4 children and im afraid of what im going to deal with. I need to know that after the blod test results were normal is there a posibility that this can be a malignant tumor and if yes what kind of procedure will i be following?