Low lying placenta

Went to our 20 week check up and everything looks great with our baby boy but the doctor said I have a low lying placenta.. He said its 1 cm away from the cervix when it needs to be 2 cm away. He "guarantees" it will move but I can't help but worry. Has anyone else had this problem and it moved to where it needs to be? I'm trying not to worry but I really don't want a c section because I'm anemic. Anybody in the same situation with some words of encouragement? Haha