I would take it back, it looks awful in the non-professional photo - not because of you in any way, but because it looks like an un-ironed second hand dress. You've taken the photo in low lighting, but there's probably going to be several parts of low light at the wedding and it just makes it look a horrible beigey colour.
In the professional photo, I would say it's 40s-50s. It's giving older minor royal family.