I'm pregnant; will my scoliosis get worse?

Unlikely. Usually a scoliosis will progress while you still are growing or if a curve has exceeded 50 degrees in size or if you become osteoporotic. Occasionally, if the scoliosis is in the lower back, it may progress due to degenerative changes but not pregnancy. Since this is not a case of teenage pregnancy, your scoliosis will not get worse.
No. Your spine curvature will not worsen during pregnancy. However, the ligaments in the body relax a bit during pregnancy. So if the curvature in your spine caused some muscle spasm/aches before pregnancy, those symptoms may worsen. Exercises can help, but new back pain or changes should be discussed with your doctor.