Hello! I recently had an ultrasound of my bladder and the doctor said …

Hello! I recently had an ultrasound of my bladder and the doctor said that the cervix is shortened. She also asked me if I didn't know about this? Well, I kind of didn't know, I went through two screenings, the ultrasound during hypertonus, already 21 weeks pregnant, and only now am I learning about it. Should I be worried?