Concerns about low lying placenta

Found out at my anatomy scan today that I have a low lying placenta. Not touching my cervix but it's close to my cervix. Never had this before.  I'm very upset and worried because I really don't want to have a c section. This is my fourth baby and all have been vaginal. 
My OB isn't too concerned but said she has to keep an eye on it. Anyone ever had this? How did it turn out?