My mri came back showing a 2.1 x 1.7 cm pineal region mass..should i be worried...

Unfortunately, yes.: Masses in the pineal region of the brain have a relatively broad range of possible causes, including both benign and malignant tumors. Most masses in this region are malignant germ cell tumors, which fortunately have a high cure rate. Because imaging studies cannot differentiate benign from malignant causes, a biopsy performed by a neurosurgeon must be done to determine the precise diagnosis.