ok so my doctor checked my cervix and said it was low now and maybe 1/2 cm dialated.. how big is 1/2 a cm ?? I know I could look at a ruler but I don't have one at the moment is it like the size of my pinkie finger or smaller? and strep b what exactly is this(I know if you test positive they will put you on antibodics for labor and delivery but that's all my doctor explained)