If you are looking for some edge to your look---I totally forgot about your pixie cut. That can tweak a girly looking lace dress into a much edgier style. (We really noticed this when my youngest daughter donated her lovely long hair to Locks or Love and then shaved off the rest...) She has a much different "look" now, and the same garments come off quite differently. (Hair has grown out now but still a very edgy style.)
And for what it's worth, to my parents' recent 60th wedding anniversary (a dress-up affair--I wore my sparkly LBD with matching coat, and killer-for-me heels), she wore a belted chiffon tiered black dress, with black sheer tights and shiny black oxfords (and a purple fedora) and looked quite posh.
Which brings me to, would you consider getting a pair of dressier black oxfords instead? Also, I was thinking you might tie a colourful (for you--maybe a jewel purple or deep green) ribbon sash, or satin rose, at the waist of that lace dress? (Wait, is it navy rather than black?)
Anyway, I love the look of those ballet flats, here's hoping they stay on!