Lauren, nylon lace over acetate taffeta can be found in several eras--on your dress, it's the styling more than anything, and, as Nicole says, also the color--taken with the fabric. Although certainly the lace-over-taffeta construction was rampant in the 50s!
I'm inclined to put this at the late 50s myself (but it could be very early 60s). Kind of hard for me to tell without holding it in my hands. I love this style of dress and have had several, including at least 2 or 3 I have now. They've all carried the 1963 and earlier Union label; if you look carefully on yours, you might find one. My own dresses of this sort that have had any hip swag or drape, etc., have always "felt" and looked more 50s to me, when holding it in person. Can't say "exactly" why.... Might be the more involved detailing yours has. That may not be any kind of "accurate" vintage rule, but that's just what my own dresses in this style have given me the feeling of. FWIW....