My Trip Back In Time

When I was in Woodstock, I thought it appropriate to browse for old vinyl records and vintage clothes. I found a pretty dress that I'm guessing is about fifty years old. It has that era's style and the material feels very old.

I'm showing the dress to you here with two questions. First, do you have a more accurate estimate of the period this dress is from? And second, do you like it better with or without a petticoat? (I tried it both ways.)

Thanks!