Low lying placenta

I was told at 20 weeks that my placenta was low and had to do a follow up sonogram last night to see if it had moved up and it hasn't . The technician told me I would most likely have to have another sonogram and if it hasn't moved I am guaranteed a c section . I was not planning on a c section at all and am a little bummed if that's how it turns out . Anyone have there's move up from now until delivery ?