It depends. Which part of your knees is hurting? If it’s muscle soreness, that’s normal.
It’s most likely normal.
Make sure you’re doing proper stretches or yoga to release tension in your body before working out.
Try to pinpoint the location of the pain and describe what it feels like to better understand the cause.
Also, what type of workouts are you doing? If you’re focusing heavily on legs, you may experience more pain.